Bicyclic lactone intermediates for 16-substituted prostaglandins
Patent 4237276 Issued on December 2, 1980. Estimated Expiration Date: 
June 19, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 19, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesProstaglandin intermediate 3-Lower alkanoyloxy-2-(2-propenyl)-5-(2-propenylcarbonyloxy)-2-cyclohexen-1-ones 2-Oxo-cyclopenta[b]furan-5-carboxylic acid esters Cis-13-PGF2.sub. analogs 2A,2B-Dihomo-11-deoxy-17(substituted phenyl)-18,19,20-trinor-PGE2 compounds and their corresponding esters Patent #: 4029693 InventorsAssigneeApplicationNo. 06/050267 filed on 06/19/1979US Classes:549/312, Acyclic carbon chain containing carbon to carbon unsaturation attached directly or indirectly to the lactone ring by nonionic bonding549/311, The bicyclo ring system consists of two five-membered rings987/110Quaternary phosphonium compounds (C)a-P-(H)b wherein a+b=4, a=1-4, b=1-3, (9/54; 9/54A1; 9/54A1+W; 9/54A1+W2)ExaminersPrimary: Jiles, Henry R.Assistant: Fan, Jane T. Attorney, Agent or FirmInternational ClassesC07C 405/00 (20060101)C07D 307/00 (20060101) C07D 307/935 (20060101) C07D 309/00 (20060101) C07D 309/12 (20060101) C07F 9/00 (20060101) C07F 9/54 (20060101) DescriptionSUMMARY OF THE INVENTIONIn accordance with this invention, a new process has been discovered for preparing prostaglandin active compounds of the formula: ##STR1## wherein R4 is hydrogen or lower alkyl, R2 is hydroxy; R3 is hydrogen or taken together withR2 forms oxo; R1 is hydrogen, lower alkyl, CH2 OR1 '; or --COOR1 '; R1 ' is hydrogen or lower alkyl; R is fluoro, lower alkyl or trifluoromethyl; R', is hydrogen, fluoro or lower alkyl; and the dotted bond can be optionallyhydrogenated; from a compound of the formula ##STR2## wherein R1 is as above. This process is extremely valuable in preparing a compound of formula I in their optically active form. Among the compounds of I are the novel compounds ##STR3## wherein R1, R2, R3 and R4 are as above, R9 is trifluoromethyl or fluoro and R9 ' is lower alkyl, hydrogen and fluoro with the proviso that when R9 ' islower alkyl or hydrogen, R9 is trifluoromethyl and the dotted bond can be optionally hydrogenated; and their optically active antipodes. The compound of formula I-A and their optically active antipodes are also novel compounds. The compounds of formula I-A have cardiovascular activity, induce labor in pregnant females; are useful forterminating pregnancies and for combatting gastrohyperacidity. The compounds of formula I-A are also useful as bronchodilators and have anti-ulcerogenic properties. DETAILED DESCRIPTION OF THE INVENTION As used throughout this application, the term "lower alkyl" includes both straight chain and branched chain alkyl groups having from 1 to 7 carbon atoms such as methyl and ethyl. As also used herein, the term "lower alkanoic acids" comprehendsan alkanoic acid of 1 to 7 carbon atoms such as formic acid and acetic acid. As further used herein, the term "halogen" or "halo", unless otherwise stated, comprehends fluorine, chlorine, bromine and iodine. In the process of this invention, all compounds having one or more asymmetric carbon atoms can be produced as racemic mixtures. These racemic mixtures which are obtained can be resolved at the appropriate steps in the process of this inventionby methods well known in the art discussed more fully below, whereupon subsequent products may be obtained as the corresponding optically pure enantiomers. In the pictorial representation of the compounds given throughout this application, a thickened taper line ( ) indicated a substituent which is in the beta-orientation (above the plane of the molecule), a dotted line (---) indicates a substituentwhich is in the alpha-orientation (below the plane of the molecule) and a wavy line ( ) indicates a substituent which is in either the alpha- or beta-orientation or mixtures of these isomers. It is to be understood that the pictorial representations ofthe compounds given throughout the specification are set forth for convenience and are to be construed as inclusive of other forms including enantiomers and racemates and are not to be construed as limited to the particular form shown. As also used herein, the term "aryl" signifies mononuclear aromatic hydrocarbon groups such as phenyl, tolyl, etc. which can be unsubstituted or substituted in one or more positions with a lower alkylenedioxy, a halogen, a nitro, a lower alkyl ora lower alkoxy substituent, and polynuclear aryl groups such as naphthyl, anthryl, phenanthryl, azulyl, etc., which can be substituted with one or more of the aforementioned gorups. The preferred aryl groups are the substituted and unsubstitutedmononuclear aryl groups, particularly phenyl. The term "aryl lower alkyl" comprehends groups wherein aryl and lower alkyl are as defined above, particularly benzyl. As still further used herein, the term "carboxy protected with a group convertible thereto by hydrolysis" comprehends any conventional organic acid protecting group which can be removed by hydrolysis. The preferred organic acid protecting groupsare the esters. Any conventional ester that can be hydrolyzed to yield the acid can be utilized as the protecting group. Exemplary esters useful for this purpose are the lower alkyl esters, particularly methyl and ethyl esters, the aryl esters,particularly phenyl ester and the aryl lower alkyl esters, particularly benzyl ester. As used herein, the term "hydrolyzable ester or ether group" designates any ester or ether which can be hydrolyzed to yield the hydroxy group. Exemplary ester groups useful for this purpose are those in which the acyl moiety is derived from alower alkanoic, an aryl lower alkanoic, phosphoric, carbonic or a lower alkane dicarboxylic acid. Among the acids which can be utilized to form such ester groups are the acid anhydrides and the acid halides, preferably chlorides or bromides, with thelower alkanoic acid anhydrides, e.g., acetic anhydride and caproic anhydride, the aryl lower alkanoic acid anhydrides, e.g., benzoic acid anhydrides, lower alkane dicarboxylic acid anhydrides, e.g., succinic anhydride, and chloroformates, e.g.,trichloroethylchloroformate, being preferred. A suitable ether protecting group is, for example, the tetrahydropyranyl ether or 4-methoxy-5,6-dihydro-2H-pyranyl ether. Others are arylmethyl ethers such as benzyl, benzyhydryl, or trityl ethers oralpha-lower alkoxy lower alkyl ethers, for example, methoxymethyl or allylic ethers, or trialkyl silyl ethers such as trimethyl silyl ether or dimethyl tert-butyl silyl ethers. The compounds of formula I wherein R2 and R3 form an oxo group, i.e., the compounds of the formula: ##STR4## wherein R4, R1, R and R' are as above; and the dotted bond can be optionally hydrogenated; are useful in the same manner as prostaglandin E2. The compounds of formula I-C are especially valuable for preventing hyperacidity in the stomach, as antiulcerogenic and for broncho-dilation and lowering blood pressure. On the other hand,the compounds of formula I where R2 is hydroxy and R3 is hydrogen, i.e. the compounds of the formula: ##STR5## wherein R4, R1, R and R' are as above and the dotted bond can be optionally hydrogenated; are useful in the same manner as prostaglandin F2 α. The prostaglandins E1, E2 and F2 α have the ability to modify the activity of the alimentary and reproductive smooth muscles to block mucous and enzyme secretions by the stomach, to stimulate the synthesis of adrenalcorticoids, to modify blood pressure and liplysis. Since the compounds of formulae I-C, and I-D have prostaglandin E1, E2 and F2 activity, the compounds of formulae I-C and I-D also possess these valuable properties. Furthermore, thecompounds of formula I-C and I-D are active in the same manner as these prostaglandins in inducing labor and pregnancy in females and for therapeuticaly terminating pregnancy. The compounds of formula I-C are useful in the same manner as theprostaglandin E2 in that they lower blood pressure and inhibit blood platelet aggregation. On the other hand, the compounds of formula I-D are blood pressure raising agents in the same manner as prostaglandin F2 α. That the compounds of formula I-C are effective anti-ulcerogenic compounds can be seen by the fact that the ED50 of a compound such as 7-[3 alpha methyl-5-oxo-2-beta-(3alpha-hydroxy-4-trifluoromethyl-4-methyl-1-trans-octenyl)-1-alpha-cyclopen tyl]-cis-5-heptenoic acid is 0.47 i.p. and 0.0001 p.o. when administered to rats by the following test: Rats were fasted 16 hours prior to the subcutaneous administration of Indomethacin at 100 mg/kg. Simultaneously with the Indomethacin dose, the test compounds were administered intraperitoneally at three dose levels and dosed orally at six doselovels. These doses of the test compounds were repeated every thirty minutes for six hours (12 doses). After six hours, the animals were killed and the stomachs were examined for ulceration or hemmorrhage. Protection from incidence of ulceration wasused to determine activity. Five mice were used per dose level ED50 values were calculated. The compounds of formula I can be used by the pharmaceutical and veterinary arts in a variety of pharmaceutical or veterinary preparations. In these preparations, the new compounds are administerable in the form of tablets, pills, powders,capsules, injectables, solutions, suppositories, emulsions, dispersions, feed pre-mixes and in other suitable forms. The pharmacuetical or veterinary preparations which contain the compound of formula I are conveniently admixed with a non-toxicpharmaceutical organic carrier or a non-toxic pharmaceutical inorganic carrier. Typical of pharmaceutically acceptable carriers are, for example, water, gelatin, lactose, starches, magnesium stearate, talc, vegetable oils, polyalkylene glycols,petroleum jelly and other conventionally employed pharmaceutically acceptable carriers. The pharmaceutical preparations may also contain non-toxic auxiliary substances such as emulsifying, preserving and wetting agents and the like, as for example,sorbitan monolaurate, triethanol amine oleate, polyoxyethylene sorbitan, dioctyl sodium sulfosuccinate and the like. The daily dose administered for the compounds will of course vary with the particular novel compounds employed because of the very potency of the compounds, the chosen route of administration and the size of the recipient. The dosageadministered is not subject to definite bounds but it will usually be in effective amounts of the pharmacologically function of the prostaglandin. Representative of a typical method for administering the prostaglandin compounds of formula I is by theinjectable type administraiton route. By this route, a sterile solution containing the prostaglandin of formula I can be administered intravenously at the rate of 0.01 microgram to 0.15 microgram per day per kilogram of body weight. The compound to beadministered by the injectable route is in a form suitable for injection such as mixed with a sterile aqueous solution having incorporated therein an agent that delays adsorption such as aluminium monosterate and the like. For administering the compounds of formula I to domestic animals or laboratory animals, the compounds are prepared in the form of a food pre-mix such as mixing with dried fish meal, oatmeal and the like and the prepared pre-mix is added to aregular feed thereby administering the compound to the domestic or laboratory animal in the form of a feed. Depending upon the particular form of the compound of formula I desired, the compound of formula II which is utilized as a starting material can be either a racemate or can be in the form of its optical antipodes. In preparing the compound of formula I, the compound of formula II is converted to a compound of the formula: ##STR6## wherein R, R1 and R' are as above; and R6 is hydroxy protected with a hydrolyzable ether or ester group. In preparing the compound of formula III, the compound of formula II is first converted to a compound of the formula: ##STR7## wherein R, R1 and R' are as above; by reaction with either a phosphorane of the formula: ##STR8## wherein R, andR' are as above, R10, R10 ' and R10 " are aryl or di(lower alkylamino); and Y.sup.(-) is halogen or a phosphonate of the formula: ##STR9## wherein R and R' are as above; and R15 and R15 ' are aryl, aryloxy or lower alkoxy. The compound of formula IV is next reduced to a compound of the formula: ##STR10## wherein R1, R and R' are as above; and the free hydroxy group is etherified or esterified to form the compound of formula III. The reaction of the compound of formula II with the phosphonium salt of formula V-A to produce a compound of formula IV is carried out via a Wittig reaction. Any of the conditions conventional in Wittig reactions can be utilized in carrying outthis reaction. The reaction of the compound of formula II with the phosphonate of formula V-B to produce a compound of formula IV is carried out via a Horner reaction. Any of the conditions conventional in Horner type reactions can be utilized in carrying outthis reaction. The compound of formula VI can be obtained by treating the compound of formula IV with a reducing agent. In carrying out this reaction, any conventional reducing agent which will selectively reduce a keto-group to a hydroxy group can beutilized. Preferred reducing agents are the hydrides, particularly the aluminum hydrides, such as the alkali metal aluminum hydrides and the borohydrides, such as the zinc borohydride or the alkali metal borohydrides, with sodium borohydride being quiteparticularly preferred. In carrying out this reaction, temperature and pressure are not critical, and the reaction can be carried out at room temperature and atmospheric pressure or at elevated or reduced temperatures and pressures. Generally, it ispreferred to carry out this reaction at a temperature of from -30° C. to this reflux temperature of the reaction mixture. This reduction reaction can be carried out in the presence of an inert organic solvent. Any conventional inert organicsolvent can be utilized in carrying out this reaction, such as the conventional, inert organic solents hereinbefore mentioned. Among the preferred solvents are methanol, dimethoxy ethylene glycol and the ethers, such as tetrahydrofuran, diethyl etherand dioxane. The compound of formula VI may be separated into its two isomers by conventional means to produce one isomer of the formula: ##STR11## wherein R1, R and R' are as above, and the other isomer of the formula: ##STR12## wherein R1, R' andR are as above. Any conventional means of separation such as column chromatography, vapor phase chromatography, etc., can be utiized to carry out this separation. Either of these isomers can be utilized in accordance with this reaction to produce thecompound of formula I. The configuration of the hydroxy group on the octenyl side chain will be carried through the process of this invention so that the hydroxy group on the octenyl side chain in the compound of formula I will have the sameconfiguration as it has in the starting material of formula VI-A or VI-B. The compound of formulae VI, VI-A and VI-B can be converted to a compound of the formula III by esterifying or etherifying the free hydroxy group with a hydroxylyzable ether or ester protecting group. This esterification or etherification can becarried out by conventional esterification procedures. Among the preferred hydrolyzable ester groups are lower alkanoyloxy with acetoxy being especially preferred. Among the preferred hydrolyzable ether groups are included tetrahydropyranyl. The compound of formula III is converted to a compound of formula I ##STR13## via the following intermediates ##STR14## wherein R, R1, R' and R6 are as above; ##STR15## R1, R, R' and R6 are as above. The compound of formula III is converted to the compound of formula X by treating the compound of formula III with a reducing agent. In carrying out this reaction, any conventional reducing agent which will selectively reduce a keto-group to ahydroxy-group can be utilized. Among the reducing agents are included the hydrides, as well as alkali metal borohydrides, with di-isobutyl aluminum hydride being particularly preferred. Also, this reaction can be carried out utilizing di-(branchedchain lower alkyl)boranes such as bis(3-methyl-2-butyl)borane. In carrying out this reaction, temperature and pressure are not critical and the reaction can be carried out at room temperature and atmospheric pressure or elevated or reduced temperaturesand pressures. Generally, it is preferred to carry out this reaction at a temperatures of from -70° C. to room temperature (30° C.). This reduction reaction can be carried out in the presence of an inert organic solent. Anyconventional inert organic solvents can be utilized in carrying out this reaction. Among the preferred solvents are dimethoxy ethylene glycol, and the ethers such as tetrahydrofuran, diethyl ether and dioxane. The compound of formula XI is obtained from the compound of formula X by reacting the compound of formula X with phosphonium salts of the formula: ##STR16## wherein R10, R10, R10 " is as above; and Y is halogen. In accordance with this invention, it is found that the compound of formula X will react with the compound of formula XII to produce a compound of the formula XI with a predominantly cis double bond at the 5 position of the acid chain in asolvent medium containing hexamethylphosphoramide utilizing sodium bis-trimethylsilylamide as a base. If solvents other than hexamethylphosphoramide or bases other than sodium bis-trimethylsilylamide are utilized, the compound of formula XI may form inpoorer yields. However, conventional inert organic solvents may be mixed with the hexamethylphosphoraide to form the solvent medium in accordance with this invention. If other solvents are utilized, these solvents can be conventional inert organicsolvents. On the other hand, the solvent system can contain only the hexamethylphosphoramide. Therefore, this reaction is carried out utilizing hexamethylphosphoramide as the solvent and sodium bis-trimethylsilyl-amide as the base. In carrying outthis reaction, temperature and pressure are not critical and this reaction can be carried out at room temperature and pressure. However, if desired, higher or lower temperatures can be utilized. Generally, it is preferred to carry out this reaction ata temperature of from 0° to 50° C. The compound of formula XI is converted to the compound of formula I-D by aqueous acid hydrolysis where the hydroxy group is protected via an ether linkage. Any conventional method of ether hydrolysis can be utilized. Among the preferredmethods of ether hydrolysis is by treating the compound of formula XI with an aqueous inorganic acid. On the other hand, where R6 forms an ester linkage, the hydroxy group can be regenerated by treatment with a base in an aqueous medium. Anyconventional method of ester hydrolysis can be utilized in this conversion. Among the preferred bases is aqueous sodium hydroxide. On the other hand, the compound of formula XI above can be converted to a compound of the formula: ##STR17## wherein R1, R and R' are as above; via an intermediate of the formula: ##STR18## wherein R6, R, R1 and R' are as above. The compound of formula XI is converted to a compound of formula XIV by treating the compound of formula XI with an oxidizing agent. Any conventional oxidizing agent which will convert a hydroxy group to an oxo group can be utilized in carryingout this reaction. Among the preferred oxidizing agents are chromate oxidizing agents such as chromium trioxide. Any of the conditions conventional in utilizing these oxidizing agents can be utilized to carry out this reaction. The compound of formulaXIV is converted to the compound of formula XIII by hydrolysis in the same manner as described in connection with the hydrolysis of a compound of formula XI. The compounds of formula XI, XIII, XIV and I-D can be converted to a compound of the formula: ##STR19## wherein R1, R2, R3, R and R' are as above; by hydrogenation. Any conventional method of hydrogenation such as catalytichydrogenation can be utilized to carry out this conversion. Among the preferred methods of hydrogenation is by reacting these compounds with hydrogen in the presence of a noble metal catalyst such as platinum or palladium under conditions conventionalfor such hydrogenation. After hydrogenation, the protecting group on the hydrogenated compounds of formula XI or XIV can be removed by hydrolysis. The compounds of formulae I-D, I-E and XIII can be converted to a compound of the formula: ##STR20## wherein R1, R2, R3, R and R' are as above; R7 is lower alkyl; and the dotted bond can be optionally hydrogenated; by esterification with diazomethane or a reactive derivative of a lower alkanol such as a lower alkyl halide. Any conventional conditions utilized in esterification can be utilized in forming the compound of formula I-F from the compounds offormulae I-D, I-E and XIII. On the other hand, the compound of formula I-F can be formed from the compounds of the formulae XI or XIV where R6 is hydroxy protected with a hydroxyzable ether group by esterification as described above to form acompound of the formula: ##STR21## wherein R1, R', R2, R3, R and R7 are as above; and R6 " is hydroxy protected with a hydrolyzable ether group and the dotted bond can be optionally hydrogenated. The compound of formula I-G is converted to the compound of formula I-F by conventional ether hydrolysis as described above. The compounds of formula VB other than compounds where when R' is hydrogen, R is trifluoromethyl are prepared by reacting a lithium salt of the formula: ##STR22## wherein R15 is as above; with a compound of the formula: ##STR23## whereinR25 is lower alkyl; R" is fluoro, lower alkyl or trifluromethyl; R''' is hydrogen, fluorine or lower alkyl with the proviso that when R" is trifluoromethyl, R''' is other than hydrogen. Any of the conditions conventional for reacting a lithium salt with an ester to form an addition product can be used in this reaction. In accordance with this invention, the compound of formula V-B can be produced from a compound of the formula: ##STR24## wherein R, R' and R25 are as above via the following intermediates ##STR25## wherein R', R are as above; and X ishalogen. The compound of formula XIX-A is converted to the compound of formula XXII by acid hydrolysis. Any conventional method of acid hydrolysis can be utilized to affect this conversion. Generally this hydrolysis is carried out at from 20° C.to 120° C. in the presence of an aqueous mineral acid such as sulfuric acid. The compound of formula XXII is converted to the compound of formula XXIII by treating with a halogenating agent. Any conventional halogenating agent can be utilizedto affect this conversion. Among the preferred halogenating agents are included: oxalyl chloride and thionyl chloride, phosphorous pentachloride. Any of the conditions conventional in utilizing these halogenating agents can be utilized in carrying outthis conversion. The compound of formula XXIII can be converted to the compound of formula XXIV by reaction with diazomethane under conditions conventional in reacting an acid halide with diazomethane. The compound of formula XXIV is converted to the compound offormula XXV by treatment with a gaseous hydrohalide acid such as gaseous hydrogen bromide under conditions conventional for converting a diazo compound to a halide. The compound of formula XXV is converted to a compound of formula V-B by reaction with atri(lower alkyl) phosphite under conditions conventional for this reaction. The compound of formula XXV can also be converted to the compound of formula V-A by reaction with a tri [aryl or di(lower alkyl)amino]phosphine under conditions conventional forthis reaction. The compound of formula XIX-A where R is CF3, i.e. a compound of the formula ##STR26## where R' and R25 are as above can be prepared from a compound of the formula: ##STR27## where R' and R25 are as above by reacting the compoundof formula XXVI with sulfur tetrafluoride. In carrying out this reaction, the sulfur tetrafluoride is reacted with the compound of formula XXVI in a closed container at a temperature of from 20° to 85° C. Generally from about 1 to 4moles of the sulfur tetrafluoride is present per mole compound of formula XXVI. Amounts of the sulfur tetrafluoride greater than four moles per mole of the compound of formula XXVI may be present in the reaction medium. If desired, acid catalystsand/or a solvent may be present in the reaction medium. Any conventional inert organic solvent, preferably the halogenated hydrocarbon solvents such as methylene chloride may, if desired, be present in the reaction medium. If desired, any conventionalacid catalyst such as hydrofluoric acid, boron trifluoride, etc. can be added to in the reaction medium. On the other hand, no solvent and/or acid catalyst need be added to the reaction medium. Of the compounds of formula XIX-B, the compounds where R' is a lower alkyl and fluoro are new compounds. The compound of formula V-A other than those compounds where when R' is hydrogen, R is trifluoromethyl, can also be prepared by reacting a compound of the formula XXIII with a compound of the formula ##STR28## wherein R10, R10 ' andR10 " are as above utilizing conditions conventional for forming Wittig reactants. The compound of formula V-B can also be prepared by reacting the compound of formula XXIII with a compound of the formula ##STR29## where M is lithium and copper. This reaction is carried out utilizing any of the conditions conventional forreacting a metal salt with an acid halide to form an addition product. In accordance with this invention, a new means is provided for producing the compound of the formula II where R1 is methyl or --COOR1 ', in optically active form, i.e. an optically active compound of the formula: ##STR30## whereinR21 is methyl, --COOR', or CH2 OR1 '; and R1 ' is as above; from a racemate of the formula ##STR31## In accordance with this aspect of this invention, the racemate of formula XXIX is treated with a suitable optically active resolving agent of the formula ##STR32## wherein R27 is ##STR33## tolyl, naphthyl, phenyl or naphthyl or phenylsubstituted with nitro or halo; R29 is tolyl, naphthyl, phenyl or napthyl or phenyl substituted with nitro or halo, R28 is --CH2 R31 ; and R31 is hydrogen, lower alkyl, hydroxy or lower alkoxy to produce an optically active salt of the formula: ##STR34## wherein R27 and R28 are as above; The salt is then neutralized to produce the desired optically active isomer of formula: ##STR35## In accordance with this invention, the racemate of formula XXIX is treated with the suitable optically active resolving agent of formula XXX in its desired optically active form. The optically active form of the compound of formula XXX willdetermine which optically active compound of formula XXIX-A is isolated Where R29 and R27 is naphthyl or phenyl, these groups can be unsubstituted. On the other hand, the naphthyl and phenyl group can be substituted with a halo or nitrosubstituent. The substituents can be in either the ortho, meta or para positions. Among the preferred optically active resolving agents of formula XXX are included the optically active forms of alpha-methyl benzyl amine, alpha-methyl p-nitrobenzylamine, alpha-(1-naphthyl)ethyl amine, or 1-phenyl-2-amino-3-substituted-1-propanol where the 3-substituent is substituted with a lower alkyl, hydroxy, or lower alkoxy radical. In preparing the optically active salt of the formula XXIX-A, the racemate is treated with the suitable optically active form of the compound of formula XXX. This treatment takes place in an inert organic solvent medium. Any conventional inertorganic solvent medium can be utilized for this salt formation. Among the preferred organic solvents are lower alkanols such as ethanol, acetonitrile, lower alkyl ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dioxane, formamide. In carrying out this treatment, temperature and pressure are not critical, and the treatment can be carried out at room temperature and atmospheric pressure. On the other hand, higher temperatures can be utilized. Generally, it is preferred to carryout the formation of the salt at a temperature of from 20° C. to 85° C. Generally the use of higher temperatures in the salt formation is an aid to the later crystallization of the salt of formula XXIX-A. In this manner, a saturatedsolution of the salt of formula XXIX-A can be formed at a higher temperature. Upon lowering the temperature to room temperature, the salt of formula XXIX-A can crystalize out of solution. On the other hand, any conventional method of crystallizationcan be utilized to obtain the desired optically active salt of formula XXIX-A as a crystalline material. The optically active salt of formula XXIX-A can be converted to the optically active isomer of formula XXIX-B by neutralization. Any conventional method of neutralization such as treating the compound of formula XXIX-A with an inorganic acid canbe utilized to produce the compound of formula XXIX-B. The compound of formula XXIX or its optically active antipodes can be converted to the compound of formula II-B where R21 is --COOH or its optically active antipodes via the following intermediate: ##STR36## where R25 is as above or itsoptically active antipodes. The compound of formula XXIX is converted to the compound of formula XXXI by first forming its aci-nitro salt by treatment with an alkali metal lower alkoxide, preferably sodium methoxide. In carrying out this reaction, temperatures of from-50° to 35° C. are utilized, with temperatures at -35° C. to -20° C. being preferred. This reaction can be carried out in a lower alkanol. The aci-nitro salt derived from the compound of formula XXIX is converted to thecompound of formula XXXI by treatment with sulfuric acid in a lower alkanol. In carrying out this reaction, temperatures of from -50° C. to 35° C. are utilized. The compound of formula XXXI is converted to the compound of formula II-Bwhere R21 is --COOH by aqueous acid hydrolysis. Any conventional method of aqueous acid hydrolysis can be utilized to affect this conversion. If desired, the compound of formula II-B where R21 is --COOH can be esterified by conventionalprocedures. On the other hand, the compounds of the formula XXIX-B, either as racemates or as an optically active isomer, can be converted to the compound of II-B where R21 is --CH3, in its optically active form or as a racemate via the followingintermediates: ##STR37## wherein X is halogen. The compounds of formula XXIX-B either as racemates or in its optically active form, can be converted to the compound of formula XXXII by treatment with a borane reducing agent. Generally for safety purposes, the borane is in the form of acomplex with methylsulfide or tetrahydrofuran. In carrying out this reaction, any of the conditions conventional in borane reduction can be utilized. This borane reduction produces the compound of formula XXXII. The compound of formula XXXII isconverted to the compound of formula XXXIII by treatment with a halogenating agent. Any conventional method of halogenating can be utilized to affect the conversion of the compound of the formula XXXII to the compound of the formula XXXIII. Inaccordance with a preferred embodiment of this invention, the compound of formula XXXII is treated with a halogen such as iodine, or bromine in the presence of triphenylphosphine. the compound of formula XXXIII is converted to the compound of theformula II-B where R21 is --CH3 by treating the compound of formula XXIII with a borohydride reducing agent such as sodium cyanoborohydride. Any of the conditions conventional in utilizing this borohydride reducing agent can be utilized toaffect this conversion. The compound of formula XXXII is the compound of formula II-B where R21 is --CH2 OH. This compound can be converted to the compound of III-B where R21 is --CH2 OR7 by etherification in the conventional manner with areactive derivative of a lower alkanol acid. The compound of formula II-B where R21 is ##STR38## can be prepared from the compound of formula II-B where R21 is --COOH by esterification. In accordance with another aspect of this invention, the compound of formula V-A and V-B can be produced in optically active form through the use of the compound of formula XXIII with an asymmetric carbon atom, i.e. a compound of the formula:##STR39## wherein R11 is fluoro, lower alkyl or trifluoromethyl; R11 ' is hydrogen, fluoro, or lower alkyl; with the proviso that R11 and R11 ' are not the same substituent or n-butyl. In this procedure, the racemic compound of formula XXIII-A is reacted with the optically active isomer of the formula XXX to form the optically active amide of the formula ##STR40## wherein R11 and R11 ' are as above and R27 andR28 are as above; as a diasteriomeric mixture. Any conventional method of reacting an amine with an acid halide can be used to form the compound of formula XL. Among the preferred compounds of formula XXX for use in the resolution are α-methyl-p-nitro benzyl amine or 1-phenyl-2-amino-b 3-unsubstituted or substituted-1-propanol in their optically active form which produce amides of the compound offormula XL, i.e. ##STR41## wherein R11 and R11 ' are as above or ##STR42## wherein R11 and R11 ' are as above, and R31 is hydrogen, hydroxy, lower alkyl or lower alkoxy. The diastereoisomers of formula XL can be separated by conventional techniques such as chromotography. Generally, it is preferred to utilize high pressure chromotography to carry out this separation. The optically active form of the compound of formula XL can be converted to the optically active form of the compound of formula XXII by treating the optically active form of the compound of formula XL with a dilute inorganic mineral acid such asfrom 1 to 10 normal aqueous hydrochloric acid. In accordance with a preferred embodiment, the compound of formula XL-A in its optically active form is converted to the optically active compound of formula XXII by first reducing the nitro group to an amino group to produce a compound of theformula ##STR43## wherein R11 and R11 ' are as above. The optically active form of the compound of formula XL-A is converted to the compound of XLI by hydrogenation. Any conventional method of catalytic hydrogenation utilizing conventional hydrogenation catalysts such as palladium can be utilizedto affect this conversion. The optically active form of the compound of formula XLI is converted to the optically active form of the compound of formula XXII by acid cleavage. Any conventional method of acid hydrolysis can be utilized to carry out thisreaction. The use of the aforementioned means has been found to produce the optical isomers of the compound of formula XXII and XXIII in good yields. The compound of formula XXII and XXIII are very difficult compounds to resolve in view of the fact thatthey contain either a secondary or tertiary fluoro or trifluoromethyl. This fluorine or trifluoromethyl group is very reactive and upon acid treatment will form side products such as by elimination of a hydrogen and fluorine to form a double bond and bythe formation of a hydroxy group rather than a fluoro substituent. It has been found that the use of the aforementioned means provides an efficient method for resolving a compound of formula XXII or XXIII without the danger of forming side products. The reduction of the nitro group at the para position in the compound of formula XL-A to an amino group in the compound of formula XLI allows the subsequent cleavage to take place without the formation of undesirable side products. Therefore, the twoaforementioned means allow the compound of formula XXII and XXIII to be resolved in high yields without the formation of undesirable by-products. In accordance with a preferred embodiment of this invention, the optical isomer of 1-phenyl-2-amino-3-methoxy propanol is preferably utilized when R11 ' is lower alkyl and R11 is fluorine or trifluoromethyl and α-methylp-nitrobenzylamine is utilized when R11 ' is hydrogen and R11 is fluorine or trifluoromethyl. The optical antipodes of the formula XXII and XXIII can be converted to form the optically active antipode of formulae V-A or V-B. This optically active center will be carried through the conversion of the compound of formula XXII and XXIII tothe compounds of formulae V-A or V-B and on to the prostaglandin compounds of formula I which are optically active about the C-16 position. EXAMPLE 1 3,3aR,4,5,6,6aS-Hexahydro-4R-nitromethyl-5R-carboxy-2H-cyclopenta[b]furan-2 -one A solution of 62 g (0.27 mol) of racemic 3,3abeta,4,5,6,6abeta-hexahydro-4beta-nitromethyl-5alpha-carboxy-2H-cyclop enta[b]furan-2-one in 3.0 l of acetonitrile was warmed to 65° C. and mixed with a solution of 27 g (0.16 mol) ofR-( )-α-methyl-p-nitrobenzyl amine in 0.7 l of acetonitrile. The solution was allowed to cool to 25° C. and after 5 hr. at this temperature, the crystal crop was filtered. Three recrystallizations from acetonitrile yielded 21.8 g (41%)of amine salt; mp 181°-2°dec, [α]D -36.3° (1% in DMSO). Evaporation of the combined mother liquors from the recrystallizations gave 24 g of crude salt which gave an additional 12.9 g of pure material after fourrecrystallizations from acetonitrile. The combined salts (34.7 g) were mixed with saturated NaCl solution (100 ml), 4 NHCl (50 ml) and ethyl acetate (300 ml). This mixture was filtered, and the ethyl acetate layer separated and evaporated to dryness togive 20.5 g (100%) of 3,3aR,4,5,6,6aS-hexahydro-4R-nitromethyl-5R-carboxy-2H-cyclopenta[b]furan- 2-one, mp. 103°-105° C., [α]D -65.4° (1% in CH3 CN) after recrystallization from ethyl acetate/hexane. Calc. for C9 H11 NO6 : C 47.19, H 4.84, N 6.11; Found: C 47.16, H 5.04, N 6.18. EXAMPLE 2 3,3aS,4,5,6,6aR-Hexahydro-4S-nitromethyl-5S-carboxy-2H-cyclopenta[b]furan-2 -one By the procedure of Example 1, racemic 3,3abeta,4,5,6,6abeta-hexahydro-4-beta-nitromethyl-5alpha carboxy-2H-cyclopenta[b]furan-2-one was resolved with S-(-)-α-methyl-p-nitrobenzyl amine to give3,3aS,4,5,6,6aR-hexahydro-4S-nitromethyl-5S-carboxy-2H-cyclopenta[b]furan- 2-one; mp. 103°-105°, [α]D 65.2° (1% in CH3 CN). Calc. for C9 H11 NO6 : C 47.19, H 4.84, N 6.11; Found: C 47.35, H 5.05, N 6.18. EXAMPLE 3 3,3aR,4,5,6,6aS-Hexahydro-4S-nitromethyl-5R-hydroxymethyl-2H-cyclopenta[b]f uran-2-one Borane-methyl sulfide complex (25 ml, 0.25 mol) was added dropwise over a 30 minute period to an ice cold solution of 3,3aR,4,5,6,6aS-hexahydro-4R-nitromethyl-5R-carboxy-2H-cyclopenta[b]furan- 2-one (45.8 g, 0.2 mol) in ethyl acetate (1 l). Theice bath was removed and the reaction stirred at RT for 20 hr. After this period, methanol (300 ml) was carefully added and the mixture was evaporated to constant weight at reduced pressure. The crude material was taken-up in 400 ml of methanolfollowed by evaporation to constant wt. to give 43 g (100%) of 3,3aR,4,5,6,6aS-hexahydro-4S-nitromethyl-5R-hydroxymethyl-2H-cyclopenta[b] furan-2-one. An analytically pure sample was prepared by column chromatography over silica gel using 2:3 ethylacetate/benzene as the eluent to give the pure alcohol as a colorless oil, [α]D -31.9° (1% in dioxane). Calc. for C9 H13 NO5 : C 50.23, H 6.09, N 6.51; Found: C 50.51, H 6.08, N 6.41. EXAMPLE 4 3,3aR,4,5,6,6aS-Hexahydro-4S-nitromethyl-5R-methyl-2H-cyclopenta[b]furan-2- one Iodine (81.3 g, 0.32 mol) was added in 4-5 g portions over a 20 minute period to a stirred solution of 3,3aR,4,5,6,6aS-hexahydro-4S-nitromethyl-5R-hydroxymethyl-2H-cyclopenta[b] furan-2-one (66.3 g, 0.308 mol.) and triphenylphosphine (83.8 g,0.32 mol.) in hexamethylphosphoramide (1 l) at RT. Thin layer analysis indicated complete conversion to 3,3aR,4,5,6,6aS-hexahydro-4S-nitromethyl-5R-iodomethyl-2H-cyclopenta[b]fur an-2-one within 5 hr. The ppt. of triphenylphosphine oxide was filteredand the filtrate was mixed with sodium cyanoborohydride (50 g, 0.8 mol.) and warmed to 70° C. for 18 hr. The reaction mixture was poured into a separatory funnel containing sat. NaCl solution (1 l.), water (1 l), and ethyl acetate (2 l). Theorganic phase was separated, dried (MgSO4) and evaporated to constant wt. at reduced pressure. The majority of the HMPA was removed from the residual material by a bulb to bulb distillation at 70°-80°/0.1 mm and the residue purifiedby column chromatography over silica gel using 0-10% ethyl acetate/benzene as the eluent to give 51.5 g (84%) of 3,3aR,4,5,6,6aS-hexahydro-4S-nitromethyl-5R-methyl-2H-cyclopenta[b]furan-2 -one as a colorless oil; [α]D -48.87° (1% inCH3 CN). Calc. for C9 H13 NO4 : C 54.27, H 6.58, N 7.03; Found: C 54.47, H 6.57, N 6.98. EXAMPLE 5 3,3aR,4,5,6,6aS-Hexahydro-4S-dimethoxymethyl-5R-methyl-2H-cyclopenta[b]fura n-2-one A solution of 3,3aR,4,5,6,6aS-hexahydro-4S-nitromethyl-5R-methyl-2H-cyclopenta[b]furan-2 -one (13.66 g, 68.8 mmol) in 140 ml (70 mmol) of 0.5 M sodium methoxide/methanol was added dropwise to a rapidly stirred solution of conc. sulfuric acid (165ml) in methanol (650 ml) at -40° C. The resulting solution was added dropwise, via a double-tipped needle, to a rapidly stirred slurry of potassium bicarbonate (775 g), water (1 l), and ethyl ether (700 ml). This mixture was filtered and theorganic layer separated, dried (Na2 SO4) and solvents evaporated at reduced pressure. The residual oil was purified by column chromatography over silica gel using ether as the eluent to give 13.2 g (90%) of3,3aR,4,5,6,6aS-hexahydro-4S-dimethoxymethyl-5R-methyl-2H-cyclopenta[b]fur an-2-one as a colorless oil; [α]D -34.6° (1% in CH3 CN). Calc. for C11 H18 O4 : C 61.66, H 8.47; Found: C 61.72, H 8.47. EXAMPLE 6 3,3aR,4,5,6,6aS-Hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one A mixture of 3,3aR,4,5,6,6aS-hexahydro-4S-dimethoxymethyl-5R-methyl-2H-cyclopenta[b]fur an-2-one (15.1 g, 0.07 mol), trifluoroacetic acid (25 ml), water (25 ml) and chloroform (300 ml) was vigorously stirred at RT for 3 hr. The layers wereseparated and the water layer extracted with 2×50 ml of CHCl3. The combined organic layers were washed with sat. NaHCO3 solution, dried (MgSO4) and evaporated to constant weight to give 11.3 g (96%) of oily3,3aR,4,5,6,6aS-Hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one, which was not further purified. An analytical sample was prepared by column chromatography over silica gel using ether as the eluent to give3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one as a colorless oil; [α]D -38.06° (1% in CH3 CN). Calc. for C9 H12 O3 : C 64.27, H 7.19; Found: C 64.06, H 7.38. EXAMPLE 7 3,3aR,4,5,6,6aS-Hexahydro-4R-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5R-methyl -2H-cyclopenta[b]furan-2-one A solution of 16.5 g (66 mmol) of dimethyl (3,3-dimethyl-2-oxoheptyl) phosphonate in 1,2-dimethoxy ethane (50 ml) was added dropwise to a stirred slurry of 3.12 g (65 mmol) of 50% sodium hydride-mineral oil in 1,2-dimethoxyethane (500 ml) under apositive argon atm. at RT. After 2.5 hr., a solution of 3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one in 1,2-dimethoxyethane (100 ml) was added dropwise and the mixture stirred for 4 hr. at RT. After this time, thereaction mixture was placed in a separatory funnel with 100 ml of sat. NaCl soln. and 1 l of ether. The layers were separated and the organic layer washed with 2×50 ml of sat. NaCl soln., dried (MgSO4) and evaporated to constant weight togive 22.5 g of a dark oil. Purification by column chromatography on silica gel (benzene) gave 11.27 g (63%) of 3,3aR,4,5,6,6aS-hexahydro- 4R-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5R-methyl-2H-cyclopenta[b]furan-2- one. Recrystallization from ether gavecolorless crystals; mp 59°-61°, [α]D 7.00° (1% in CH3 CN). Calc. for C18 H28 O3 : C 73.94, H 9.65; Found: C 73.65; H 9.66. EXAMPLE 8 3,3aR,4,5,6,6aS-Hexahydro-4R-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5R-m ethyl-2H-cyclopenta[b]-furan-2-one and 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one A solution of 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5R-methy l-2H-cyclopenta[b]furan-2-one (2.07 g) in 10 ml of methanol was added to a solution of 0.67 g of sodium borohydride in 25 ml of methanol at -23° C.After 1 hr, the reaction mixture was acidified to pH 5.5 with 1 N H2 SO4. The methanol was removed at reduced pressure and the residue extracted with 3×30 ml of ether. Evaporation of the ether gave 2.2 g of crude material which waspurified by column chromatography over silica gel using 30% ethyl acetate/benzene as the eluent to give 1.3 g of 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]-furan-2-one as a colorless oil,[α]D 5.62° (1% in CH3 CN). Calc. for C18 H30 O3 : C 73.43, H 10.27; Found: C 73.51, H 10.31. Additionally, there was obtained 0.7 g of 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]-furan-2-one as a colorless oil; [α]D -30.0° (1% in CH3 CN). Calc. for C18 H30 O3 : C 73.43, H 10.27; Found: C 73.23, H 10.30. EXAMPLE 9 3,3aR,4,5,6,6aS-Hexahydro-4R-[4,4-dimethyl-3R(2-tetrahydropyranyloxy)-1-tra ns-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol To a solution of 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one (3.02 g, 10.2 mmol) in methylene chloride (70 ml) was added 1.1 ml of dihydropyran and 1 mg of p-toluenesulfonic acid. After 3 hrs. at RT, several drops of sat. NaHCO3 solution were added and the reaction evaporated to constant wt. at reduced pressure to give 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-dimethyl-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one. This crude material was then mixed with 250 ml of dry toluene. The flask was sealed under a positive argon atm. and cooled to -78° C. With rapid stirring, 7 ml (10.5 mmol) of 1.5 Mdi(isobutyl) aluminum hydride/hexane was added dropwise. After 30 min., the reaction mixture was mixed with ether (500 ml), sat. NaCl solution (50 ml) and 2 N HCl (20 ml). The layers were separated and the organic layer dried (MgSO4) and thesolvents removed at reduced pressure. The residual oil was purified by column chromatography using 3:7 parts by volume ether/hexane as the eluent to give 3.22 g (83%) of 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-dimethyl-3R(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol as a colorless oil; [α]D 7.93° (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.59; Found: C 72.44; H 10.72. EXAMPLE 10 Nat-11R,16,16-Trimethyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis- 5,trans-13-dienoic acid Sodium bis (trimethylsilyl) amide (6.7 g, 36 mmol) was dissolved in 100 ml of HMPA and the resulting solution degassed from a stream of argon. This solution was transferred under a positive argon atm via a double-tipped needle to a slurry of(4-carboxybutyl)triphenylphosphonium bromide [7.96 g (18 mmol) dried at 100°/0.3 mmHg] in 100 ml of HMPA. This mixture was stirred under a positive argon atm until all the solid dissolved and the deep-red color of the Wittig reagent formed. Asolution of 3.22 g (8.42 mmol) of 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-dimethyl-3R(2-tetrahydropyranyloxy)-1-tr ans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol in 50 ml of HMPA was added via a double-tipped needle. After stirring 1 hr at RT, 2.5 ml ofacetic acid was added and the majority of the HMPA was removed by a bulb to bulb distillation at 80°-90°/0.2 mm. The residual brown slug was dissolved in 300 ml of water. Sodium hydroxide (5.3 g) was added and the mixture stirredovernight at RT. The ppt. of triphenylphosphine oxide was filtered and the filtrate acidified to pH 5 with 2 N HCl. Ether extraction gave 5.63 g of material after evaporation to constant wt. Purification by column chromatography on silica gel (0-25%EtOAc/bz) gave 3.06 g (78%) of nat-11R,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis -5,trans-13-dienoic acid as a colorless oil; [α]D 3.12 (1% in CH3 CN). Calc. for C28 H48 O5 : C 72.37, H 10.41; Found: C 72.27, H 10.47. EXAMPLE 11 Nat-11R,16,16-trimethyl-9S,15R-dihydroxyprosta-cis-5,trans-13-dienoic acid Nat-11R,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxyprosta-cis-5 ,trans-13-dienoic acid (500 mg) was warmed at 40° C. for 18 hr. with 50 ml of a mixture of acetic acid-water-tetrahydrofuran (55-30-15). After this time, thesolvent was evaporated at reduced pressure and the residual oil purified by column chromatography on silica gel using 0-60% ethyl acetate/benzene as the eluent to give 400 mg (97%) of nat-11R,16,16-trimethyl-9S,15R-dihydroxyprosta-cis-5,trans-13-dienoicacid as a colorless oil; [α]D 53.04° (0.6% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.60; Found: C 71.94, H 10.87. EXAMPLE 12 Nat-11R,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid To a rapidly stirred solution of 650 mg (1.4 mmol) of nat-11R,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis -5,trans-13-dienoic acid in 100 ml of ether-acetone (4:1) at RT was added 80 drops of 2.0 M Jones reagent (CrO3-H2 SO4). After 20 min, the reaction was diluted with ether (150 ml) and washed with 20 ml portions of water until neutral. The organic solution was dried (MgSO4) and evaporated to dryness to give 658 mg of crudenat-11R,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9-oxoprosta-cis-5,tra ns-13-dienoic acid as a light yellow oil. This oil was mixed with 50 ml of a mixture of acetic acid-water-THF (55-30-15) and warmed to 40° C. for 20 hr. After this time,the solvent was evaporated and the residual oil purified by column chromatography on silica gel (0-50% EtOAc/bz) to give 523 mg (98%) of nat-11R,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid as a colorless oil: [α]D-51.54° (1% in CHCl3). Calc. for C28 H46 O5 : C 72.69, H 10.02; Found: C 73.02, H 10.15. EXAMPLE 13 Methyl nat-11R,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoate To 500 mg (1.3 mmol) of nat-11R,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid in 50 ml of ether was added distilled diazomethaneether until the yellow color persisted longer than 5 min. The solvent was evaporated and theproduct twice purified by high pressure liquid chromatography using first 25% EtOAc/hexane followed by 20% EtOAc/benzene to give 480 mg (93%) of methyl nat-11R,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoate as a colorless oil;[α]D -51.63° (1% in CH3 CN). Calc. for C24 H40 O4 : C 73.43, H 10.27; Found: C 73.35, H 10.33. EXAMPLE 14 3,3aR,4,5,6,6aS-Hexahydro-4R-[4,4-dimethyl-3S(2-tetrahydropyranyloxy)-1-tra ns-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol By the procedure of Example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-dimethyl-3S-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol; a colorless oil, [α]D -38.34° (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.59; Found: C 72.76, H 10.50. EXAMPLE 15 Nat-11R,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis- 5,trans-13-dienoic acid By the procedure of Example 10, 3,3aR,4,5,-6,6aS-hexahydro-4R-[4,4-dimethyl-3S-(2-tetrahydropyranyloxy)-1- trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol was converted tonat-11R,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis -5,trans-13-dienoic acid; a colorless oil, [α]D 40.39° (1% in CH3 CN). Calc. for C28 H48 O5 : C 72.37, H 10.41; Found: C 72.54, H 10.49. EXAMPLE 16 Nat-11R,16,16-trimethyl-9S,15S-dihydroxyprosta-cis-5,trans-13-dienoic acid By the procedure of Example 11, nat-11R,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9S-hydroxyprosta-cis- 5,trans-13-dienoic acid was converted to nat-11R,16,16-trimethyl-9S,15S-dihydroxyprosta-cis-5,trans-13-dienoic acid; a colorless oil,[α]D 12.4° (0.5% in CH3 CN). Calc. for C13 H40 O4 : C 72.59, H 10.60; Found: C 72.32, H 10.83. EXAMPLE 17 Nat-11R,16,16-trimethyl-15S-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid By the procedure of Example 12, nat-11R,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9S-hydroxy-prosta-cis -5,trans-13-dienoic acid was converted to nat-11R,16,16-trimethyl-15S-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid; a colorless oil,[α]D -83.70° (1% in CH3 CN). Calc. for C23 H38 O4 : C 72.97, H 10.12; Found: C 72.88, H 10.12. EXAMPLE 18 3,3aS,4,5,6,6aR-Hexahydro-4R-nitromethyl-5S-hydroxymethyl-2H-cyclopenta[b]f uran-2-one By the procedure of Example 3, the compound 3,3aS,4,5,6,6aR-hexahydro-4R-nitromethyl-5S-carboxy-2H-cyclopenta[b]furan- 2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4R-nitromethyl-5S-hydroxymethyl-2H-cyclopenta[b] furan-2-one as a colorlessoil; [α] 32.72° (1% in dioxane). Calc. for C9 H13 NO5 : C 50.23, H 6.09, N 6.51; Found: C 50.26, H 6.12, N 6.70. EXAMPLE 19 3,3aS,4,5,6,6aR-Hexahydro-4R-nitromethyl-5S-methyl-2H-cyclopenta[b]furan-2- one By the procedure of Example 4, 3,3aS,4,5,6,6aR-hexahydro-4R-nitromethyl-5-S-hydroxymethyl-2H-cyclopenta[b ]furan-2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4R-nitromethyl-5S-methyl-2H-cyclopenta[b]furan-2 -one, a colorless oil,[α]D 49.15° (1% in CH3 CN). Calc. for C9 H13 NO4 : C 54.27, H 6.58, N 7.03; Found: C 54.10, H 6.65, N 6.97. EXAMPLE 20 3,3aS,4,5,6,6aR-Hexahydro-4R-dimethoxymethyl-5S-methyl-2H-cyclopenta[b]fura n-2-one By the procedure of Example 5, 3,3aS,4,5,6,6aR-hexahydro-4R-nitromethyl-5S-methyl-2H-cyclopenta[b]furan-2 -one was converted to 3,3aS,4,5,6,6aR-hexahydro-4R-dimethoxymethyl-5S-methyl-2H-cyclopenta[b]fur an-2-one; a colorless oil [α]D 35.68° (1% in CH3 CN). Calc. for C11 H18 O4 : C 61.66, H 8.47; Found: C 61.44; H 8.49. EXAMPLE 21 3,3aS,4,5,6,6aR-Hexahydro-4R-formyl-5S-methyl-2H-cyclopenta[b]furan-2-one By the procedure of Example 6, 3,3aS,4,5,6,6aR-hexahydro-4R-dimethoxymethyl-5S-methyl-2H-cyclopenta[b]fur an-2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4R-formyl-5S-methyl-2H-cyclopenta[b]furan-2-one; a colorless oil. EXAMPLE 22 3,3aS,4,5,6,6aR-Hexahydro-4S-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5S-methyl -2H-cyclopenta[b]furan-2-one By the procedure of Example 7, 3,3aS,4,5,6,6aR-hexahydro-4R-formyl-5S-methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5S-methy l-2H-cyclopenta[b]furan-2-one; a colorless solidmp 57°-8°, [α]D -15.16° (1% in CHCl3). Calc. for C18 H28 O3 : C 73.94, H 9.65; Found: C 73.87, H 9.49. EXAMPLE 23 3,3aS,4,5,6,6aR-Hexahydro-4S-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5S-m ethyl-2H-cyclopenta[b]furan-2-one and 3,3aS,4,5,6,6aR-Hexahydro-4S-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5S- methyl-2H-cyclopenta[b]furan-2-one By the procedure of Example 8, 3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3-oxo-1-trans-octenyl)-5S-methy l-2H-cyclopenta[b]furan-2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5S-methyl-2H-cyclopenta[b]furan-2-one; a colorless oil, [α]D -18.13° (1% in CH3 CN). Calc. for C18 H30 O3 : C 73.43, H 10.27; Found: C 73.23, H 10.50. and 3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5S- methyl-2H-cyclopenta[b]furan-2-one; a colorless oil, [α]D 39.83° (1% in CH3 CN). Calc. for C18 H30 O3 : C 73.43, H 10.27; Found: C 73.41, H 10.10. EXAMPLE 24 3,3aS,4,5,6,6aR-Hexahydro-4S-[4,4-dimethyl-3S-(2-tetrahydropyranyloxy)-1-tr ans-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol By the procedure of Example 9, 3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3S-hydroxy-1-trans-octenyl)-5S- methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aS,4,5,6,6aR-hexahydro-4S-[4,4-dimethyl-3S-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol; a colorless oil, [α]D zero (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.59; Found: C 72.60, H 10.42. EXAMPLE 25 Ent-11S,16,16-Trimethyl-15S-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis-5 ,trans-13-dienoic acid By the procedure of Example 10, 3,3aS,4,5,6,6aR-hexahydro-4S-[4,4-dimethyl-3S-(2-tetrahydropyranyloxy)-1-t rans-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol was converted toent-11S,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid; a colorless oil, [α]D -28.67° (1% in CH3 CN) Calc. for C28 H48 O5 : C 72.37, H 10.41; Found: C 72.24, H 10.46. EXAMPLE 26 Ent-11S,16,16-Trimethyl-9R,15S-dihydroxyprosta-cis-5,trans-13-dienoic acid By the procedure of Example 11, ent-11S,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid was converted to ent-11S,16,16-trimethyl-9R,15S-dihydroxyprosta-cis-5,trans-13-dienoic acid; a colorless oil,[α]D -47.74° (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.60; Found: C 71.93, H 10.57. EXAMPLE 27 Ent-11S,16,16-Trimethyl-15S-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid By the procedure of Example 12, ent-11S,16,16-trimethyl-15S-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid was converted to ent-11S,16,16-trimethyl-15S-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid; a colorless oil,[α]D 63.9° (1% in CHCl3). Calc. for C23 H38 O4 : C 72.97, H 10.12; Found: C 73.03, H 10.19. EXAMPLE 28 3,3aS,4,5,6,6aR-Hexahydro-4S-[4,4-dimethyl-3R-(2-tetrahydropyranyloxy-1-tra ns-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol By the procedure of Example 9,3,3aS,4,5,6,6aR-hexahydro-4S-(4,4-dimethyl-3R-hydroxy-1-trans-octenyl)-5 S-methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aS,4,5,6,6aR-Hexahydro-4S-[4,4-dimethyl-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol; a colorless oil, [α]D -10.32° (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.59; Found: C 72.44, H 10.47. EXAMPLE 29 Ent-11S,16,16-Trimethyl-15R-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis-5 ,trans-13-dienoic acid By the procedure of Example 10, 3,3aS,4,5,6,6aR-hexahydro-4S-[4,4-dimethyl-3R-(2-tetrahydropyranyloxy)-1-t rans-octenyl]-5S-methyl-2H-cyclopenta[b]furan-2-ol was converted toent-11S,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid; a colorless oil [α]D -53.52° (1% in CH3 CN). Calc. for C28 H48 O5 : C 72.37, H 10.41; Found: C 72.22, H 10.60. EXAMPLE 30 Ent-11S,16,16-Trimethyl-9R,15R-dihydroxyprosta-cis-5,trans-13-dienoic acid By the procedure of Example 11, ent-11S,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid was converted to ent-11S,16,16-trimethyl-9R,15R-dihydroxyprosta-cis-5,trans-13-dienoic acid; a colorless oil,[α]D -7.07° (1% in CH3 CN). Calc. for C23 H40 O4 : C 72.59, H 10.60; Found: C 72.25, H 10.69. EXAMPLE 31 Ent-11S,16,16-Trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid By the procedure of Example 12, ent-11S,16,16-trimethyl-15R-(2-tetrahydropyranyloxy)-9R-hydroxyprosta-cis- 5,trans-13-dienoic acid was converted to ent-11S,16,16-trimethyl-15R-hydroxy-9-oxoprosta-cis-5,trans-13-dienoic acid; a colorless solid, mp54°-5° C., [α]D 123.96° (1% in CHCl3). Calc. for C23 H38 O4 : C 72.97, H 10.12; Found: C 73.02, H 10.00. EXAMPLE 32 2-Fluorahexanoic acid To a suspension of sodium hydride (1.08 mol) in 1200 ml of toluene was added dropwise 235 g (1.08 mol) of diethyl n-butylmalonate. To the resulting clear solution of the sodium salt was then bubbled perchloryl fluoride while the the temperaturewas maintained below 10° C. When the calculated amount of perchloryl fluoride had been added a stream of argon was bubbled through the solution for a short period of time. The mixture was filtered and the toluene removed under reduced pressure. The remaining oil was distilled to give 223 g, b.p. 78° (0.1 mmHg) of diethyl-2-fluoro-n-butylmalonate. To a solution of 500 ml of 4 N aqueous sodium hydroxide was added 223 g of diethyl-2-fluoro-n-butylmalonate and the mixture stirred for 4 hr. At the end of this time the mixture was placed under vacuum at 40° C. and most of the alcoholremoved. The mixture was then acidified to pH 2, salted and extracted with a 1:1 solution of ether-pentane. The organic layer was dried and the residue decarboxylated at 150° for 4 hr. The residue was dissolved in pentane, charcoaled anddried. The pentane was removed under vacuum at 10° C. and the residue distilled to give 2-fluoro hexonoic acid b.p. 75° (16 mmHg). EXAMPLE 33 N-[(S)-alpha-methyl-p-nitrobenzyl]-alpha-fluoro-R-hexanamide and N-[(S)-alpha-methyl-p-nitrobenzyl]-alpha-fluoro-S-hexanamide To 50 g of 2-fluoro hexonoic acid was added 3 eq. of thionyl chloride. After stirring for 1 hr. at room temperature, the mixture was heated to 60°-65° and stirred at this temperature for 3 hr. The residual thionyl chloride wasremoved under vacuum and the residue distilled to give 2-fluoro hexanoyl-chloride b.p. 50-55 (20 mmHg). To a solution of 2 eq. of S(-)2-methyl-p-nitro benzylamine in ether at 0° was added dropwise a solution of 2-fluoro hexanoylchloride in ether. After the addition was complete, the amine salt was filtered. The ether layer washed withdilute acid and then dried. The ether was removed under reduced pressure and the residual amides separated via high pressure liquid chromatography to give N-[(S)-alpha-methyl-p-nitrobenzyl]-alpha-fluoro-(S)-hexanamide mp 92°-93.5° [α]D25 -124.29° (CHCl3) and N-[(S)-alpha-methyl-p-nitrobenzyl]-alpha-fluoro-(R)-hexanamide mp 84.5°-86.5°, [α]D25 -66.25° (CHCl3). EXAMPLE 34 N-[(S)-alpha-Methyl-p-aminobenzyl]alpha-fluoro-R-hexanamide A mixture of 19 g of N-[(S)-alpha-methyl-p-nitrobenzyl]alpha-fluoro-R-hexanamide, 0.5 g of 10% Pd/C and 250 ml and ethanol was hydrogenated until the theoretical uptake of hydrogen had been completed. The mixture was filtered and the solventsremoved under reduced pressure. Crystallization of the residue from hexane-ether afforded N-[(S)-alpha-methyl-p-aminobenzyl]alphafluoro R-hexanamide mp 86°-88° C. [α]D25 -111.78 (CHCl3). EXAMPLE 35 N-[(S)-alpha-Methyl-p-aminobenzyl]alpha-fluoro-S-hexanamide Starting from N-[(S)alpha-methyl-p-nitrobenzyl]alpha-fluoro-S-hexanamide by the procedure in Example 34 was obtained N-[(S)-alpha-methyl-p-aminobenzyl]alpha-fluoro-S-hexanamide mp 80°-82° [α]D25 -151.58(CHCl3). EXAMPLE 36 2R-Fluoro hexanoic acid methyl ester A mixture of 169 g of N-[(S)-alpha-methyl-p-aminobenzyl]alpha-fluoro-R-hexanamide and 170 ml of 30% sulfuric acid was heated at 90° for 10 hr. The mixture was cooled and extracted with pentane. The pentane solution was dried and thesolvent removed under reduced pressure of 10°. The residue was then treated with an ethereal solution of diazomethane, stirred for 1 hr. and the solvents removed under vacuum. The residue was then distilled to give 2R-fluoro hexanoic acidmethyl ester b.p. 72°-74° (16 mmHg); [α]D25 12.7° (CHCl3). EXAMPLE 37 2S-Fluoro hexanoic acid methyl ester By the procedure described in Example 36 from N[(S)-alpha-methyl-p-aminobenzyl]alpha-fluoro-S-hexanamide was obtained 2S-fluoro-hexanoic acid methyl ester b.p. 70°-72° (20 mmHg) [α]D25 -12.97° (CHCl3). EXAMPLE 38 Dimethyl-(2-oxo-3S-fluoroheptyl)phosphonate To a solution of 15.1 g of methyl dimethylphosphonate in 120 ml. dry THF was added with stirring at -78° 1 eq. of butyl lithium in hexane. After stirring for 0.5 hr at this temperature, 8 g of 2S-fluoro hexanoic acid methyl ester wasadded and the mixture stirred at -78° C. for 1 hr and then allowed to warm to 0°. Pentane (200 ml) and 27.5 ml of 4 N H2 SO4 was added and the mixture separated. The aqueous phase was extracted with pentane and the organiclayers combined and dried. The solvent was removed under reduced pressure and the residue distilled to give 11.2 g of dimethyl-(2-oxo-3S-fluoroheptyl)phosphonate b.p. 98° (0.2 mmHg), [α]D25 -63.03 (CHCl3). EXAMPLE 39 Dimethyl-(2-oxo-3R-fluoroheptyl)phosphonate By the procedure described in Example 38, 2R-fluoro-hexanoic acid methyl ester was converted to dimethyl-(2-oxo-3R-fluoroheptyl)phosphonate b.p. 98° (0.2 mmHg), [α]D25 63.61 (CHCl3). EXAMPLE 40 2-Fluoro-2-methylhexanoic acid ethyl ester To a solution of 0.9 mol of lithium cyclohoxyl isopropryl amide in one liter of THF was added 100 g of 2-fluoro hexonoic acid ethyl ester at -78°. After stirring for 20 min. at this temperature was added 116 ml of methyl iodide. After 1hr. one liter of pentane was added and the mixture acidified to pH3 with 1 N H2 SO4. The organic layer was separated and washed with saturated aqueous NaCl solution and dried. The solvent was removed under reduced pressure and the residuedistilled to give 2-fluoro-2-methylhexanoic acid ethyl ester b.p. 115° (87 mmHg). EXAMPLE 41 2R-Fluoro-2-methyl-N-[(S)-beta-hydroxy-(S)-alpha-(methoxymethyl)-phenethyl] hexanamide and 2S-fluoro-2-methyl-N-[(S)-beta-hydroxy-(S)-alpha-(methoxy methyl)-phenethyl]hexanamide To a solution of 71 g of 2-fluoro-2-methyl hexanoic acid ethyl ester in 500 ml of glyme was added 1.1 eq. of 1 N sodium hydroxide solution. After stirring for 3.5 hr., the glyme was removed under vacuum, the residue extracted with ether and theaqueous layer acidified. The mixture was then extracted with pentane and the pentane solution dried. The solvent was then removed under vacuum to give 61 g of crude acid. The crude acid was treated with 156 g of oxalyl chloride and the solutionstirred at room temperature for 1.5 hr and then heated at 65° for 1.5 hr. The excess oxalyl chloride was then removed under vacuum and the residue distilled to give 51 g of 2-fluoro-2-methylhexanoyl chloride b.p. 60° (25-30 mmHg). To a solution of 42.1 g (0.233 mol) of (1S,2S)-1-phenyl-2-amino-3-methoxy-1-propanol and 32 ml (0.23 mol) of triethylamine in 2 liters of ether was added dropwise at 0° with stirring 38.7 g of acid chloride in 400 ml of ether. Afterstirring for 3 hr. at 0°, the amine salt was filtered and the ether solution washed with dilute acid. The ether solution was dried and the solvents removed under reduced pressure. The residue was then separated via high pressure liquidchromatography to give 36 g of 2S-fluoro-2-methyl-N-[(S)-beta-hydroxy-(S)-alpha-(methoxymethyl)-phenethyl [hexanamide mp 76°-77.5° C. [α]D25 17.50° and 37 g of2R-fluoro-2-methyl-N[(S)-beta-hydroxy-(S)-alpha-(methoxymethyl)phenethyl[h exanamide mp 94°-96° C. [α]D25 31.10 (CHCl3). EXAMPLE 42 2R-Fluoro-2-methyl hexanoic acid methyl ester A mixture of 35 g of 2R-fluoro-2-methyl-N-[(S)-beta-hydroxy-(S)-alpha(methoxymethyl)-phenethyl] hexanamide and 525 ml of 4 N HCl was refluxed for 4 hr. At the end of this time, the mixture was cooled ether added and the ether solution separatedand dried. The ether was removed under vacuum to give 18.3 g of crude acid. The crude acid was then added to an excess of diazomethane in ether and the solution stirred at 0° for 1 hr. The excess diazomethane was treated with acetic acid andthe ether solution washed with 5% sodium bicarbonate solution and dried. The ether was removed under vacuum to give 2R-fluoro-2-methyl hexanoic acid methyl ester b.p. 72°-73° (22 mmHg) [α]D25 4.1 (CHCl4). EXAMPLE 43 2S-Fluoro-2-methyl hexanoic acid methyl ester By the procedure described in Example 42, 2S-fluoro-2-methyl-N-[(S)-beta-hydroxy-(S)-alpha-(methoxymethyl)-phenethyl ]hexanamide was converted to 2S-fluoro-2-methyl hexanoic acid methyl ester b.p. 71° (22 mmHg) [α]D25-4.6 (CHCl3). EXAMPLE 44 Dimethyl-(2-oxo-3R-fluoro-3-methylheptyl)phosphonate To a solution of 23.2 g (0.187 mol) of methyl dimethyl phosphonate in 200 ml of dry THF was added 85 ml of 2.1 N butyl lithium in hexane at -78°. After stirring for 0.5 hr, 13.8 g of 2R-fluoro-2-methyl hexanoic acid methyl ester was addedat -78°. After 0.5 hr. at this temperature, the reaction was allowed to warm to 0°. Acid (4 N H2 SO4) was then added to pH7. The THF removed under reduced pressure and the residue extracted with ether. The ether solution wasdried and the solvent removed under reduced pressure to give 19.6 g of dimethyl-(2-oxo-3R-fluoro-3-methylheptyl)phosphonate b.p. 88°-91° (0.1 mmHg) [α]D25 49.15 (CHCl3). EXAMPLE 45 Dimethyl-(2-oxo-3S-fluoro-3-methylheptyl)phosphonate By the procedure described in Example 44, 2S-2-methylhexanoic acid methyl ester was converted to dimethyl-(2-oxo-3S-fluoro-3-methylheptyl)phosponate b.p. 87 (0.1 mmHg) [α]D25 -49.0 (CHCl3). EXAMPLE 46 3,3aR,4,5,6,6aS-Hexahydro-4R-(4S-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2H -cyclopenta[b]furan-2-one By the procedure of example 7,3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-on e was reacted with dimethyl-(2-oxo-3S-fluoroheptyl)phosphonate to give3,3aR,4,5,6,6aS-hexahydro-4R-(4S-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2 H-cyclopenta[b]furan-2-one as a colorless viscous oil. Structure in agreement with mass spectrum. EXAMPLE 47 3,3aR,4,5,6,6aS-Hexahydro-4R-(4S-fluoro-3S-hydroxy-1-trans-octenyl)-5R-meth yl-2H-cyclopenta[b]furan-2-one- and 3,3aR,4,5,6,6aS-hexahydro-4R(4S-fluoro-3R-hydroxy-1-trans-octenyl)-5R-meth yl-2H-cyclopenta[b]furan-2-one By the procedure of example 8, 3,3aR,4,5,6,6aS-hexahydro-4R-(4S-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2 H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6aS-hexahydro-4R-(4S-fluoro-3S-hydroxy-1-transoctenyl)-5R-methyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil and 3,3aR,4,5,6,6aS-hexahydro-4R-(4S-fluoro-3R-hydroxy-1-trans-octenyl)-5R-met hyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil. The mass spectra data is in agreement with structureindicated. EXAMPLE 48 3,3-aR,4,5,6,6aS-Hexahydro-4R-[4S-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-(4S-fluoro-3R-hydroxy-1-trans-octenyl)-5R-met hyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4S-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil. The mass spectra is in agreement with the structure indicated. EXAMPLE 49 nat. 11R-methyl-16S-fluoro-15R-(2-tetrahydropyranyloxy)-9S-hydroxyprosta-cis-5- trans-13-dienoic acid By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-[4S-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4S-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol, a light yellow viscous oil. By the procedure of example 10, crude 3,3aR,4,5,6,6aS-hexahydro-4R-[4S-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol was converted to nat. 11R-methyl-16S-fluoro-15R-(2-tetrahydropyranyloxy)-9S-hydroxyprosta-cis-5- trans-13-dienoic acid, a light yellow viscous oil. The mass spectra data is in agreement with the structure indicated. EXAMPLE 50 nat. 11R-methyl-16S-fluoro-9S,15R-dihydroxyprosta-cis-5-trans-13-dienoic acid By the procedure of example 11, nat. 11R-methyl-16S-fluoro-15R-(2-tetrahydropyranyloxy)9S-hydroxyprosta-cis-5-t rans-13-dienoic acid was converted to nat. 11R-methyl-16S-fluoro-9S,15R-dihydroxyprosta-cis-5-trans-13-dienoic acid. The massspectra is in agreement with the structure indicated. EXAMPLE 51 nat. 11R-Methyl-16S-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoic acid By the procedure of example 12, nat. 11R-methyl-16S-fluoro-15R-(2-tetrahydropyranyloxy)9S-hydroxyprosta-cis-5-t rans-13-dienoic acid was converted to nat. 11R-methyl-16S-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoic acid mp41°-45°, [α]D25-84.01 (CHCl3). Calc: C 68.45, H 9.03; Found: C 68.46, H 9.25. EXAMPLE 52 3,3aR,4,5,6,6aS-Hexahydro-4R-(4R-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2H -cyclopenta[b]furan-2-one By the procedure of example 7, 3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one was reacted with dimethyl-(2-oxo-3R-fluoroheptyl)phosphonate to give3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2 H-cyclopenta[b]furan-2-one as a light viscous oil. The mass spectra is in agreement with the structure indicated. EXAMPLE 53 3,3aR,4,5,6,6aS-Hexahydro-4R-(4R-fluoro-3R-hydroxy-1-trans-octenyl)-5R-meth yl-2H-cyclopenta[b]furan-2-one and 3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-3S-hydroxy-1-trans-octenyl)-5R-met hyl-2H-cyclopenta[b]furan-2-one By the procedure of example 8, 3,3aR,4,5,6,6aS-hexahydro-4R(4R-fluoro-3-oxo-1-trans-octenyl)-5R-methyl-2H -cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R(4R-fluoro-3S-hydroxy-1-trans-octenyl)-5R-methyl-2H-cyclopenta[b]furan-2-one, mp 84.5°-87°, [α]D25 -16.07 (CHCl3) and 3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-3R-hydroxy-1-trans-octenyl)-5R-met hyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil. [α]D25 9.71 (CHCl3). EXAMPLE 54 3,3aR,4,5,6,6aS-Hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans -octenyl]5R-methyl-2H-cyclopenta[b]furan-2-one By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-3R-hydroxy-1-trans-octenyl-5R-meth yl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil. EXAMPLE 55 3,3aR,4,5,6,6aS-Hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans -octenyl]-5R-methyl-2H-cyclopenta-[b]furan-2-ol By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]5R-methyl-2H cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol a colorless viscous oil. The mass spectra is in agreement with the structre indicated. EXAMPLE 56 nat. 11R-Methyl-16R-fluoro-15R-hydroxy-9S-hydroxyprosta-cis-5-trans-13-dienoic acid By the procedure of example 10, 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-ol was converted to nat. 11R-methyl-16R-fluoro-15R-(2-tetrahydropyranyloxy)9S-hydroxyprosta-cis-5-t rans-13-dienoic acid. Ths crude product was then converted by the procedure of Example 11, to give nat. 11R-methyl-16R-fluoro-15R-hydroxy-9S-hydroxyprosta-cis-5-trans-13-dienoicacid mp 50°-54°, [α]D25 47.4 (CHCl3). Anal. Calcd. for C21 H35 FO4 -- Calc. : C 68.01, H 9.52, F 5.13; Found: C 67.65, H 9.50, F 4.71. EXAMPLE 57 nat. 11R-Methyl-16R-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoic acid By the procedure of example 12, crude nat. 11R-methyl-16R-fluoro-15R-(2-tetrahydropyranyloxy)-9S-hydroxyprosta-cis-5- trans-13-dienoic acid was converted to nat. 11R-methyl-16R-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoic acid acolorless viscous oil, [α]D25 -68.78 (CHCl3). Anal. Calcd. for C21 H33 FO4 -- Calc.: C 68.45, H 9.03, F 5.16; Found: C 68.03, H 8.93, F 4.92. EXAMPLE 58 3,3aR,4,5,6,6aS-Hexahydro-4R-(4R-fluoro-4-methyl-3-oxo-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one By the procedure of example 7, 3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one was reacted with dimethyl-(2-oxo-3R-fluoro-3-methyl heptyl)phosphonate to give3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-4-methyl-3-oxo-1-trans-octenyl)-5R -methyl-2H-cyclopenta[b]furan-2-one mp 68°-70°, [α]D25 45.74 (CHCl3). EXAMPLE59 3,3aR,4,5,6,6aS-Hexahydro-4R-(3R-hydroxy-4R-fluoro-4-methyl-1-trans-octenyl )-5R-methyl-2H-cyclopenta[b]furan-2-one and 3,3aR-4,5,6,6aS-Hexahydro-4R-(3S-hydroxy-4R-fluoro-4-methyl-1-trans-octeny l)-5R-methyl-2H-cyclopenta[b]furan-2-one To a solution of 2 g of sodium borohydride in 100 ml of methanol at -30° was added a solution of 9.2 g of 3,3aR,4,5,6,6aS-hexahydro-4R-(4R-fluoro-4-methyl-3-oxo-1-trans-octenyl)-5R -methyl-2H-cyclopenta[b]furan in 50 ml of methanol. After 0.5 hr. at -30°, 1 N sulfuric acid was slowly added to pH6 and the methanol removed under reduced pressure. The residue was extracted with ether and the ether solution dried. The solvent was removed under reduced pressure and the residuechromatographed to give 3,3aR,4,5,6,6aS-hexahydro-4R-(3R-hydroxy-4R-fluoro-4-methyl-1-trans-octeny l)-5R-methyl-2H-cyclopenta[b]furan-2-one mp 55-57.5, [α]D25 7.33 (CHCl3) and3,3aR,4,5,6,6aS-hexahydro-(4R-(3S-hydroxy-4R-fluoro-4-methyl-1-trans-octen yl)-5R-methyl-2H-cyclopenta[b]furan-2-one, mp 83°-85°, [α]D25 -27.18 (CHCl3). EXAMPLE 60 3,3aR,4,5,6,6aS-Hexahydro-4R[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans- octenyl]5H-cyclopenta[b]furan-2-one By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-(3R-hydroxy-4R-fluoro-4-methyl-1-trans-octeny l)-5R-methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one. EXAMPLE 61 nat. 11R-Methyl-16R-fluoro-16-methyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxypro sta-cis-5-trans-13-dienoic acid By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-trans-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-ol. By the procedure of example 10, crude 3,3aR,4,5,6,6aS-hexahydro-4R-[4R-fluoro-3R-(2-tetrahydropyranyloxy)-1-tran s-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-ol was converted to nat. 11R-methyl-16R-fluoro-16-methyl-15S-(2-tetrahydropyranyloxy)-9S-hydroxypro sta-cis-5-trans-13-dienoic acid, a white waxy solid. EXAMPLE 62 nat. 11R,16-Dimethyl-16R-fluoro-9S,15R-dihydroxyprosta-cis-5-trans-13-dienoic acid By the procedure of example 11, nat. 11R-methyl-16R-fluoro-16-methyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxypro sta-cis-5-trans-13-dienoic acid was converted to nat. 11R,16-dimethyl-16R-fluoro-9S,15R-dihydroxyprosta-cis-5-trans-13-dienoic acid,mp 70°-73°, [α]D25 42.94° (CHCl3). Anal. calcd. for C22 H37 FO4 -- Calcd.: C 68.72, H 9.70, F 4.94; Found: C 68.78, H 9.70, F 5.08. EXAMPLE 63 nat. 11R,16-Dimethyl-16R-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoic acid By the procedure of example 12, nat. 11R-methyl-16R-fluoro-16-methyl-15R-(2-tetrahydropyranyloxy)-9S-hydroxypro sta-cis-5-trans-13-dienoic acid was converted to nat. 11R,16-dimethyl-16R-fluoro-15R-hydroxy-9-oxoprosta-cis-5-trans-13-dienoicacid, a colorless viscous liquid, [α]D25 -57.55° (CHCl3). Anal. calcd. for C22 H35 FO4 -- Calcd.: C 69.08, H 9.22, F 4.97; Found: C 68.76, H 9.19, F 4.70. EXAMPLE 64 Ethyl 2-Trifluoromethylhexanoate To a 4 liter stainless steel bomb was added 237 g. (1.26 mol) of 2-carboethoxyhexanoic acid, 260 ml. of methylene chloride, and 19 ml. of 48% hydrofluoric acid. The bomb was sealed with an assembly consisting of a rupture disk (1400-1600 psi)and a needle valve. It was then cooled in a dry ice-acetone bath for 30 minutes and evacuated to less than 10 mmHg pressure. While maintaining the bomb in the cooling bath, 600 g. (5.56 mol) of sulfur tetrafluoride was condensed into the bomb from anattached lecture bottle. The needle valve closed and the bomb was removed from the cooling bath and allowed to remain at room temperature, with only occasional agitation for 13 days. After this period of time, the bomb was vented and the residualmaterials taken up in pentane (2.2 liters), dried over NaF/MgSO4. Distillation of the filtered pentane solution gave 117 g. (44%) of ethyl 2-trifluoromethylhexanoate, b.p. 69°-76°/20 mmHg. EXAMPLE 65 2-Trifluoromethylhexanoic acid Ethyl 2-trifluoromethylhexanoate (10.05 g.) was mixed with 50 ml. of concentrated sulfuric acid and warmed to 75° C. for 20 hours. After cooling, the acid was poured onto excess ice. The resulting mixture was saturated with sodiumchloride, extracted with ether (3×100 ml.). The combined ether extracts were dried (MgSO4) and evaporated to give a residual oil which yielded 2-trifluoromethylhexanoic acid (7.50 g.) upon distillation, b.p. 80°-85°/2.8 mmHg. EXAMPLE 66 2-Trifluoromethylhexanoyl chloride 2-Trifluoromethylhexanoic acid (2.3 g.) was added dropwise to 10 g. oxalyl chloride (10 g.) and the mixture heated to reflux for 2 hours. Distillation of the reaction mixture after this time yielded 2-trifluoromethylhexanoyl chloride (2.27 g.;90%), b.p. 67°-70°/43 mmHg. EXAMPLE 67 3-Trifluoromethyl-1-bromoheptan-2-one 2-Trifluoromethylhexanoyl chloride (2.27 g.) was added dropwise to an excess of etheral diazomethane solution at 0° C. After one hour, the excess diazomethane was removed with a stream of nitrogen. The ether solution at 0° C. wasthen treated with an excess of hydrogen bromide gas. After 15 minutes, the solution was washed with saturated sodium chloride solution (3×10 ml.), dried (MgSO4) and evaporated to constant weight in a vacuum to give 2.56 g. (88%) of3-trifluoromethyl-1-bromoheptan-2-one, which was not further purified. EXAMPLE 68 Diethyl (3-trifluoromethyl-2-oxoheptyl)phosphonate A mixture of 3-trifluoromethyl-1-bromoheptan-2-one (2.50 g.) and triethylphosphite (5.1 g.) was heated to 100° C. and continuously flushed with a slow stream of nitrogen. After 6 hours, the mixture was distilled to give 2.60 g. of amixture of diethyl (3-trifluoromethyl-2-oxoheptyl)phosphonate and diethyl (3-trifluoromethylhepten-1-yl-2)-phosphate. The diethyl (3-trifluoromethyl-2-oxoheptyl)phosphonate was isolated from this mixture. EXAMPLE 69 Ethyl 2-Trifluoromethyl-2-methylhexanoate To a 90 ml. stainless steel bomb was added 6.6 g. of 2-carboethoxy-2-methylhexanoic acid, 5 ml. of dichloromethane, and 0.4 ml. of 48% hydrofluoric acid. The bomb was sealed with an assembly consisting of a rupture disk (2400-3600 psig) and aneedle valve. The bomb was then cooled in a dry ice-acetone bath and evacuated to less than 10 mmHg pressure. Sulfur tetrafluoride (15 g.) was condensed into the bomb from an attached lecture bottle. The needle valve was closed and the bomb was storedin a hood at room temperature for 3 days. After this time, the bomb was immersed to 1/3 of its length in a 60° C. bath. After warming at 60° C. for 3 days, the bomb was cooled and vented. The residual materials were taken up in pentane(250 ml.). The pentane solution was dried (NaF/MgSO4), filtered and distilled to give 3.14 g. (42%) of ethyl 2-trifluoromethylhexanoate, b.p. 79°-81° /20 mmHg. EXAMPLE 70 Diethyl (3-trifluoromethyl-3-methyl-2-oxoheptyl)phosphonate A 100 ml. flask was charged with 3.34 g. (22 mmol) of methyl diethylphosphonate and 50 ml. of tetrahydrofuran. The flask was sealed with a rubber septum, cooled to -75° C. (dry ice-acetone) and flushed with argon. To the cooledsolution was added with stirring 13.7 ml. (22 mmol) of 1.6 M n-butyllithium/hexane. After 10 minutes, 2.26 g. (10 mmol) of ethyl-2-trifluoromethyl-2-methylhexanoate was added and the mixture was allowed to warm to room temperature as the dryice-acetone bath dissipated (50 minutes). After 2 hours, the reaction was mixed with ether (200 ml.) and 2 N sulfuric acid (20 ml.). The layers were separated and the ether layer was washed with 2×20 ml. of saturated NaCl solution, dried(NaCl/MgSO4), filtered and the filtrate distilled to give 2.79 g. (84%) of diethyl 3-trifluoromethyl-3-methyl-2-methyl-2-oxo-heptylphosphonate, b.p. 94°-97°/0.15 mmHg. EXAMPLE 71 (2R)-Trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]-hexa namide and (2S)-Trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]hexa namide 2-Trifluoromethylhexanoyl chloride (8.11 g.) was added dropwise to an ice cold solution of triethylamine (4.5 g.) and (1S,2S)-1-phenyl-2-amino-3-methoxypropan-1-ol (6.7 g.) in 350 ml. of ethyl ether. The mixture was stirred for 1 hour at roomtemperature, filtered and the filtrate washed with 3×10 ml. of 2 N hydrochloric acid. The ether layer was dried (MgSO4) and the ether evaporated in vacuo to give 9.12 g. of a 1:1 mixture (m.p. 65°-76° C.) of(2R)-trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]hexa namide and (2S)-trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]hexa namide, which was separated by silica gel chromatography using 20:1 benzene-ethyl acetate. EXAMPLE 72 (2R)-2-Trifluoromethyl-2-methyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-p ropyl]hexanamide and (2S)-2-trifluoromethyl-2-methyl-N-[(1S,2 S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]hexanamide By the procedure of Example 41, 2-trifluoromethyl-2-methyl-hexanoyl chloride (2.1 g.) was reacted with (1S,2S)-1-phenyl-2-amino-3-methoxypropan-1-ol (1.5 g.) to give an oily 1:1 mixture of(2R)-2-trifluoromethyl-2-methyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2- propyl]hexanamide and (2S)-2-trifluoromethyl-2-methyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2- propyl]hexanamide, which was separated by silica gel chromatography using 20:1benzene-ethyl acetate. EXAMPLE 73 (2R)-Trifluoromethylhexanoic acid (2R)-2-Trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]hex anamide (3.5 g.) was heated to 100°-110° C. with 70 ml. of 4.5 N hydrochloric acid. After heating for 2.5 hours, the mixture was cooled, saturated withsodium chloride, and extracted with 3×50 ml. of ethyl ether. The combined ether extracts were dried (MgSO4) and the ether evaporated in a vacuum at 35° C. Distillation of the residual oil gave 1.91 g. of (2R)-trifluoromethylhexanoicacid, b.p. 83°-85°/2.6 mmHg. EXAMPLE 74 (2S)-Trifluoromethylhexanoic acid By the procedure of Example 73, (2S)-2-trifluoromethyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2-propyl]he xanamide was converted to (2S)-trifluoromethylhexanoic acid. EXAMPLE 75 (2R)-2-Trifluoromethyl-2-methylhexanoic acid By the procedure of Example 73, (2R)-2-trifluoromethyl-2-methyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2- propyl]hexanamide was converted to (2R)-2-trifluoromethyl-2-methylhexanoic acid. EXAMPLE 76 (2S)-2-Trifluoromethyl-2-methylhexanoic acid By the procedure of Example 73, (2S)-2-trifluoromethyl-2-methyl-N-[(1S,2S)-1-phenyl-1-hydroxy-3-methoxy-2- propyl]hexanamide was converted to (2S)-2-trifluoromethyl-2-methylhexanoic acid. EXAMPLE 77 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-oxo-4-trifluoromethyl-1-trans-octe nyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan To a suspension of 0.7 g. of sodium hydride in 150 ml. of diglyme was added 6 g. of dimethyl (3-trifluoromethyl)-2-oxoheptyl)phosphonate. After stirring for 1.5 hours, 5 g. of3,3abeta,4,5,6,6abeta-hexahydro-4beta-formyl-5alpha-methyl-2-oxo-2H-cyclop enta[b]furan dissolved in 30 ml. of glyme was added dropwise at 0° C. After stirring for 3 hours at room temperature, 500 ml. of diethyl ether was added and the mixturewas washed with water. The organic layer was then dried (MgSO4) and the solvent removed under reduced pressure. The residue was then washed through 75 g. of silica gel to give the above-named product. EXAMPLE 78 3,3abeta,4,5,6,6abeta-Hexahydro-4beta-(3-oxo-4-methyl-4-trifluoromethyl-1-t rans-octenyl)-5-alpha-methyl-2-oxo-2H-cyclopenta[b]furan By the procedure of Example 77, 3,3abeta-4,5,6,6abeta-hexahydro-4beta-formyl-5alpha-methyl-2-oxo-2H-cyclop enta[b]furan was reacted with dimethyl (2-oxo-3-methyl-3-trifluoromethylheptyl)phosphonate to give the above-named product. EXAMPLE 79 3,3abeta,4,5,6,6abeta-Hexahydro-4beta-(3-alpha-hydroxy-4-trifluoromethyl-1- trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan and 3,3abeta,4,5,6,6abeta-Hexahydro-4beta-(3beta-hydroxy-4-trifluoromethyl-1-trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan To a solution of 4.5 g. of 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-oxo-4-trifluoromethyl-1-trans-oct enyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan in 100 ml. of diglyme was added an excess of zinc borohydride in 50 ml. of glyme and theresulting solution stirred for 3 hours. The solution was cooled to 0° C. and treated with 200 ml. of water, 400 ml. of ether and 10 ml. of 0.5 N aqueous sulfuric acid. The ether was separated and dried (MgSO4) and the solvent removedunder reduced pressure to give 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-hydroxy-4-trifluoromethyl-1-trans -octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan. Column chromatography on silica gel utilizing diethyl ether hexane (70:30 parts by volume)then afforded first the 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-alpha-hydroxy-4-trifluoromethyl-1 -trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan and then 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3beta-hydroxy-4-trifluoromethyl-1-trans-octenyl)-5alpha-methyl-2-oxo-2 H-cyclopenta[b]furan. EXAMPLE 80 3,3abeta,4,5,6,6abeta-Hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-4-m ethyl-1-trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan and 3,3abeta,4,5,6,6abeta-Hexahydro-4beta-(3beta-hydroxy-4-trifluoromethyl-4-methyl-1-trans-octenyl)-3alpha-methyl-2-oxo-2H-cyclopenta[b]furan By the procedure of Example 79, 3,3abeta,4,5,6,6abeta-hexahydro-4alpha-(3-oxo-4-trifluoromethyl-4-methyl-1 -trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan was converted to3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-4- methyl-1-trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan and 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3beta-hydroxy-4-trifluoromethyl-4-methyl-1-trans-octenyl)-3alpha-methyl-2-oxo-2H-cyclopenta[b]furan which were separated by column chromatography in the manner of Example 61. EXAMPLE 81 3,3abeta,4,5,6,6abeta-Hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tri fluoromethyl-1-trans-octenyl]-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan A solution of 5 g. of 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-1- trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan, 12 g. of dihydropyran and 25 mg. of p-toluenesulfonic acid in 200 ml. of methylenechloride was stirred at 25° C. for 3 hours. The solution was washed with saturated sodium bicarbonate solution, the methylene chloride solution dried (MgSO4) and the volatile components evaporated under reduced pressure to give 6.4 g. ofthe above-named product. EXAMPLE 82 3,3abeta,4,5,6,6abeta-Hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tri fluoromethyl-4-methyl-1-trans-octenyl]-5alpha-methyl-2-oxo-2H-cyclopenta[b] furan By the procedure of Example 81, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-4- methyl-1-trans-octenyl)-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan was converted to the above-named product. EXAMPLE 83 3,3abeta,4,5,6,6abeta-Hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tri fluoromethyl-1-trans-octenyl]-5alpha-methyl-2H-cyclopenta[b]furan-2-ol To a solution of 5.3 g. of 3,3abeta,4,5,6,6abeta-hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tr ifluoromethyl-1-trans-octenyl]-5alpha-methyl-2-oxo-2H-cyclopenta[b]furan in 150 ml. of toluene was added dropwise at -78° C. 1equivalent of diisobutyl-aluminum hydride in the same solvent. The reaction mixture was stirred at this temperature for 2 hours after which time 20 ml. of methanol was slowly added and the mixture stirred for 2 hours at room temperature. The mixturewas then filtered through a bed of celite, the celite was washed with ethyl acetate and the solvents were then removed under reduced pressure. The residue was then washed through a column of silica gel to give the above-named product. EXAMPLE 84 3,3abeta,4,5,6,6abeta-Hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tri fluoromethyl-4-methyl-1-trans-octenyl]-5alpha-methyl-2H-cyclopenta[b]furan- 2-ol By the procedure of Example 83, 3,3abeta,4,5,6,6abeta-hexahydro-4beta[3alpha-(2-tetrahydropyranyloxy)-4-tr ifluoromethyl-4-methyl-1-trans-octenyl]-5alpha-methyl-2-oxo-2H-cyclopenta[b ]furan was converted to the above-named product. EXAMPLE 85 7-(3alpha-methyl-5alpha-hydroxy-2beta[3alpha-(2-tetrahydropyranoyloxy)-4-tr ifluoromethyl-1-trans-octenyl]-1alpha-cyclopentyl)-cis-5-heptenoic acid 3.6 g. of 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-1-trans-octenyl]-5alpha-methyl-2H-cyclopenta[b]furan-2-ol in 150 ml. of hexamethylphosphoric triamide was reacted with 2.2 equivalents of Wittigreagent generated by the reaction of 7.0 g. (0.0384 mol) of sodium bis-trimethylsilyl amide with 8.4 g. (0.19 mol) of (4-carboxybutyl)-triphenylphosphonium bromide. After stirring for thirty minutes, the mixture was acidified to pH 6.5 with dilutesulfuric acid and the hexamethylphosphoramide removed under high vacuum. The mixture was then extracted several times with ether and the ether solution dried (Na2 SO4). The solvent was then removed under reduced pressure and the residuechromatographed on silica gel to give 3.5 g. of the above-named product. EXAMPLE 86 7-{3alpha-methyl-5alpha-hydroxy-2beta[3alpha-(2-tetrahydropyranyloxy)-4-tri fluoromethyl-4-methyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid By the procedure of Example 85, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-5alpha-methyl-2H-cyclopenta[b]fura n-2-ol is converted to the above-named product. EXAMPLE 87 7-[3alpha-methyl-5-oxo-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-octe nyl)-1alpha-cyclopentyl]-cis-5-heptenoic acid To a mixture of 6 g. of chromiun trioxide and 9.5 g. of pyridine in 150 ml. of methylene chloride was added at 0° C. 4.5 g. of 7{3alpha-methyl-5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid dissolved in 50 ml. of methylene chloride. The mixture was stirred for 1 hour at room temperature and the mixture filtered through a bed of celite. The celite was washed withmethylene chloride and the combined methylene chloride solution washed with dilute hydrochloric acid to remove any remaining pyridine. The methylene chloride was then removed under reduced pressure and the residue treated with 50 ml. of 3:1 parts byvolume acetic acid/water solution at 35° C. for 15 hours. The solvents were then removed under high vacuum and the residue purified by column chromatography to give the above-named product. EXAMPLE 88 7-[3alpha-methyl-5-oxo-2beta-(3alpha-hydroxy-4-trifluoromethyl-4-methyl-1-t rans-octenyl)-1 alpha-cyclopentyl]-cis-5-heptenoic acid By the procedure of Example 87, 7-{3alpha-methyl-5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoi c acid was converted to the above-named product. EXAMPLE 89 7-[3alpha-methyl-5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-t rans-octenyl)-1alpha-cyclopentyl]-cis-5-heptenoic acid A solution of 200 mg. of 7-{3alpha-methyl-5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid in 5 ml. of 3:1 parts by volume acetic acid/water solution was kept at35° C. for 15 hours. The solvent was then removed under high vacuum and the residue purified via column chromatography to give the above-named product. EXAMPLE 90 7-[3alpha-methyl-5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-4-m ethyl-1-trans-octenyl)-1alpha-cyclopentyl]-cis-5-heptenoic acid By the procedure of Example 89, 7-{3alpha-methyl-5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoi c acid was converted to the above-named product. EXAMPLE 91 3,3abeta,4,5,6,6abeta-hexahydro-4beta(3-oxo-4-trifluoromethyl-1-trans-octen yl)-2-oxo-2H-cyclopenta[b]furan By the procedure of Example 77, dimethyl (2-oxo-3-trifluoromethylheptyl) phosphonate was reacted with 3,3abeta,4,5,6,6abeta-hexahydro-4beta-formyl-2-oxo-2H-cyclopenta[b]furan to produce the above-named product. EXAMPLE 92 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-oxo-4-methyl-4-trifluoromethyl-1-t rans-octenyl)-2-oxo-2H-cyclopenta[b]furan By the procedure of Example 77, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-formyl-2-oxo-2H-cyclopenta[b]furan was reacted with dimethyl (2-oxo-3-methyl-3-trifluoromethylheptyl)phosphonate to give the above-named product. EXAMPLE 93 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-1-t rans-octenyl)-2-oxo-2H-cyclopenta[b]furan and 3,3abeta,4,5,6,6abeta-hexahydro-4beta(3beta-hydroxy-4-trifluoromethyl-1-tr ans-octenyl)-2-oxo-2H-cyclopenta[b]furan By the procedure of Example 79, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-oxo-4-trifluoromethyl-1-trans-oct enyl)-2-oxo-2H-cyclopenta[b]furan was reacted to give 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-hydroxy-4-trifluoromethyl-1-trans-octenyl)-2-oxo-2H-cyclopenta[b]furan. Chromatography on silica gel in the manner of Example 79 afforded first the 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-1- trans-octenyl)-2-oxo-2H-cyclopenta[b]furan. Also obtained bychromatography was the 3,3abeta,4,5,6,6abeta-hexahydro-4beta(3beta-hydroxy-4-trifluoromethyl-1-tr ans-octenyl)-2-oxo-2H-cyclopenta[b]furan. EXAMPLE 94 By the procedure of Example 79, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3-oxo-4-trifluoromethyl-4-methyl-1- trans-octenyl)-2-oxo-2H-cyclopenta[b]furan was converted to 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-4-methyl-1-trans-octenyl)-2-oxo-2H-cyclopenta[b]furan and 3,3abeta,4,5,6,6abeta-hexahydro-4beta(3beta-hydroxy-4-trifluoromethyl-4-me thyl-1-trans-octenyl)-2-oxo-2H-cyclopenta[b]furan which were separated by column chromatography in the same manner asExample 79. EXAMPLE 95 By the procedure of Example 81, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-hydroxy-4-trifluoromethyl-1- trans-octenyl]-2-oxo-2H-cyclopenta[b]furan was converted to 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl-1-trans-octenyl]-2-oxo-2H-cyclopenta[b]furan. EXAMPLE 96 By the procedure of Example 81, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-(3alpha-hydroxy-4-trifluoromethyl-4- methyl-1-trans-octenyl)-2-oxo-2H-cyclopenta[b]furan was converted to3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy-4-tr ifluoromethyl-4-methyl-1-trans-octenyl]-2-oxo-2H-cyclopenta[b]furan. EXAMPLE 97 By the procedure of Example 83, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-1-trans-octenyl]-2-oxo-2H-cyclopenta[b]furan is converted to3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-1-trans-octenyl]-2H-cyclopenta[b]furan-2-ol. EXAMPLE 98 By the procedure of Example 83, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-2-oxo-2H-cyclopenta[b]furan was converted to3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-2H-cyclopenta[b]furan-2-ol. EXAMPLE 99 By the procedure of Example 85, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-1-trans-octenyl]-2H-cyclopenta[b]furan-2-ol was converted to7-(5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl -1-trans-octenyl]-1alpha-cyclopentyl)-cis-5-heptenoic acid. EXAMPLE 100 By the procedure of Example 85, 3,3abeta,4,5,6,6abeta-hexahydro-4beta-[3alpha-(2-tetrahydropyranyloxy)-4-t rifluoromethyl-4-methyl-1-trans-octenyl]-2H-cyclopenta[b]furan-2-ol was converted to7-{5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl -4-methyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid. EXAMPLE 101 By the procedure of Example 87, 7-{5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl -1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid was converted to7-{5-oxo-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-octenyl)-alpha-cy clopentyl}-cis-5-heptenoic acid. EXAMPLE 102 By the procedure of Example 87, 7{-5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl -4-methyl-1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid was converted to7-[5-oxo-2beta-(3alpha-hydroxy-4-trifluoromethyl-4-methyl-1-trans-octenyl) -1alpha-cyclopentyl]-cis-5-heptenoic acid. EXAMPLE 103 By the procedure of Example 89, 7-{5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)4-trifluoromethyl- 1-trans-octenyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid was converted to7-[5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-octenyl) -1alpha-cyclopentyl]-cis-5-heptenoic acid. EXAMPLE 104 By the procedure of Example 89, 7-{5alpha-hydroxy-2beta-[3alpha-(2-tetrahydropyranyloxy)-4-trifluoromethyl -4-methyl-1-trans-ocetnyl]-1alpha-cyclopentyl}-cis-5-heptenoic acid was converted to7-[5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-4-methyl-1-trans -octenyl)-1alpha-cyclopentyl]-cis-5-heptenoic acid. EXAMPLE 105 A tablet was prepared containing the following ingredients: ______________________________________ Per Tablet ______________________________________ 7-[3alpha-methyl-5-oxo-2beta-(3alpha-hydroxy- 4-trifluoromethyl-1-trans-octenyl)-lalpha- cyclopentyl]-cis-5-heptenoic acid 200 mg. Dicalcium phosphatedihydrate, unmilled 235 mg. Corn starch 70 mg. FD&C Yellow #5 - Aluminum Lake 25% 2 mg. Durkee Duratex* 25 mg. Calcium stearate 3 mg. Total Weight 535 mg. ______________________________________ *Hydrogenated cotton seed oil (fully saturated) All of the above ingredients were mixed until thoroughly blended in a suitable size container. The powder was filled into #2, two-piece, hard shell gelatin capsules to an approximate fill weight of 350 mg. using a capsulating machine. EXAMPLE 106 A capsule was prepared by the procedure of Example 105 except that 7-[2beta-(4-trifluoromethyl-3alpha-hydroxy-1-trans-octenyl)-5-oxo-1alpha-c yclopentyl]-cis-5-heptenoic acid was the active ingredient. EXAMPLE 107 A capsule was prepared by the procedure of Example 105 except that 7-[5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-octenyl) -1alpha-cyclopentyl]-cis-5-heptenoic acid was the active ingredient. EXAMPLE 108 A tablet was found containing: ______________________________________ Per Tablet ______________________________________ 7-[3alpha-methyl-5-oxo-2beta-(3alpha-hydroxy- 4-trifluoromethyl-1-trans-octenyl)-lalpha- cyclopentyl]-cis-5-heptenoic acid 25 mg. Dicalcium phosphatedihydrate, unmilled 175 mg. Corn startch 24 mg. Magnesium stearate 1 mg. Total Weight 225 mg. ______________________________________ The 7-[3alpha-methyl-5-oxo-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-oct enyl)-1alpha-cyclopentyl]-cis-5-heptenoic acid and corn starch were mixed together and passed through a #00 screen in Model "J" Fitzmill with hammers forward. Thispremix was then mixed with dicalcium phosphate and one-half of the magnesium stearate, passed through a #1A screen in Model "J" Fitzmill with knives forward, and slugged. The slugs were passed through a #2A plate in a Model "D" Fitzmill at slow speedwith knives forward, and the remaining magnesium stearate was added. The mixture was mixed and compressed. EXAMPLE 109 A tablet was formulated in the same manner as in Example 108 except that 7-[2beta-(4-trifluoromethyl-4-methyl-3alpha-hydroxy-1-trans-octenyl)-5-oxo -1alpha-cyclopentyl]-cis-5-heptenoic acid was the active ingredient. EXAMPLE 110 A tablet was formulated in the same manner as in Example 108 except that 7-[5alpha-hydroxy-2beta-(3alpha-hydroxy-4-trifluoromethyl-1-trans-octenyl) -1alpha-cyclopentyl]-cis-5-heptenoic acid was the active ingredient. EXAMPLE 111 To 750 ml of a 0.8 M solution of molybdenum hexafluoride in methylene chloride saturated with borontrifluoride was added at -30° 95 g of 2-keto hexanoic acid ethyl ester dissolved in 300 ml of methylene chloride. The resulting solutionwas allowed to warm to room temperature and stirred at this temperature for 3 hrs. The solution was then cooled to 0° and 500 ml of water was added. The methylene chloride solution was separated and washed with water, a sat. sodium chloridesolution and a sat. sodium bicarbonate solution. The methylene chloride solution was dried (MgSO4) and the solvent removed at atmospheric pressure. Distillation of the residue afforded 21 g of 2,2-difluoro hexanoic acid ethyl ester bp73°-75° (23 mmHg). EXAMPLE 112 Dimethyl-(2-oxo-3,4-difluoroheptyl)phosphonate To a solution of 31.8 g of methyl dimethylphosphonate in 300 ml of dry THF was added with stirring at -78° 1 eq. of butyl lithium in hexane. After stirring for 0.5 hr. at this temperature, 21 g of 2,2-difluoro hexanoic acid ethylesther was added and the mixture stirred at -78° for 1 hr. and then allowed to warm to 0°. Pentane (200 ml) and 4 N H2 SO4 was added (pH 6) and the mixture separated. The aqueous phase was extracted with pentane and theorganic layers combined and dried (MgSO4). The solvent was removed under reduced pressure and the product purified via column chromatography. Distillation afforded 20.6 g of dimethyl (2-oxo-3,3-difluoroheptyl)phosphonate bp 108°-110° (0.4 mmHg). EXAMPLE 113 3,3aR,4,5,6,6aS-Hexahydro-4R-(4,4-difluoro-3-oxo-1-trans-octenyl)-5R-methyl -2H-cyclopenta[b]furan-2-one By the procedure of example 7, 3,3aR,4,5,6,6aS-hexahydro-4S-formyl-5R-methyl-2H-cyclopenta[b]furan-2-one was reacted with dimethyl-(2-oxo-3,3-difluoroheptyl)phosphonate to give3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3-oxo-1-trans-octenyl)-5R-methy l-2H-cyclopenta[b]furan-2-one as a colorless viscous oil. Structure in agreement with mass spectrum. EXAMPLE 114 3,3aR,4,5,6,6aS-Hexahydro-4R-(4,4-difluoro-3S-hydroxy-1-trans-octenyl)-5R-m ethyl-2H-cyclopenta[b]furan-2-one and 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3R-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one By the procedure of example 8, 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3-oxo-1-trans-octenyl)-5R-methy l-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3S-hydroxy-1-trans-octenyl)-5R-methyl-2H-cyclopenta[b]furan-2-one mp 66°-67.5° and 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3R-hydroxy-1-trans-octenyl)5R-m ethyl-2H-cyclopenta[b]furan-2-one a light yellow viscous oil. The mass spectra data is in agreement with thestructures indicated. EXAMPLE 115 3,3aR,4,5,6,6aS-Hexahydro-4R[4,4-difluoro-3R-(tetrahydro-2H-2-pyranyloxy)-1 -trans-octenyl]-5R-methyl-2H-cyclopenta[b]furan-2-one By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-(4,4-difluoro-3R-hydroxy-1-trans-octenyl)-5R- methyl-2H-cyclopenta[b]furan-2-one was converted to 3,3aR,4,5,6,6aS-hexahydro-4R[4,4-difluoro-3R(tetrahydro-2H-2-pyranyloxy)-1-trans-octenyl]-5R-methyl-2H-cyclopenta-[b]furan-2-one a light yellow viscous oil. The mass spectra is in agreement with the structure indicated. EXAMPLE 116 nat.(2,E)-11R-Methyl-16,16-difluoro-15R-(tetrahydro-2H-2-pyranyloxy)-9S-hyd roxyprosta-5,13-dienoic acid By the procedure of example 9, 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-difluoro-3R-(tetrahydro-2H-2-pyranyloxy) -1-trans-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-one was converted to3,3aR,4,5,6,6aR-hexahydro-4R-[4,4-difluoro-3R-(tetrahydro-2H-2-pyranyloxy) -1-trans-octenyl]5R-methyl-2H-cyclopenta[b]furan-2-ol. By the procedure of example 10, 3,3aR,4,5,6,6aS-hexahydro-4R-[4,4-difluoro-3R-(tetrahydro-2H-2-pyranyloxy) -1-trans-octenyl]5R-methyl-2H-cyclopenta-[b]furan-2-ol was converted tonat.(2,E)-11R-methyl-16,16-difluoro-15R-(tetrahydro-2H-2-pyranyloxy)-9S-hy droxyprosta-5,13-dienoic acid a light yellow viscous oil. The mass spectra data is in agreement with the structure indicated. EXAMPLE 117 nat.(2,E)-11R-Methyl-16,16-difluoro-9S,15R-dihydroxyprosta-5,13-dienoic acid By the procedure of example 11, nat.(2,E)-11R-methyl-16,16-difluoro-15R-(tetrahydro-2H-2-pyranyloxy)-9S-hy droxyprosta-5,13-dienoic acid was converted to nat.(2,E)-11R-methyl-16,16-difluoro-9S,15R-dihydroxyprosta-5,13-dienoic acid a light yellowviscous oil. The mass spectra is in agreement with the structure indicated. EXAMPLE 118 nat.(2,E)-11R-Methyl-16,16-difluoro-15R-hydroxy-9-oxoprosta-5,13-dienoic acid By the procedure of example 12, nat.(2,E)-11R-methyl-16,16-difluoro-15R-(tetrahydro-2H-2-pyranyloxy)-9S-hy droxyprosta-5,13-dienoic acid was converted to nat.(2,E)-11R-methyl-16,16-difluoro-15R-hydroxy-9-oxoprosta-5,13-dienoic acid a light yellowviscous oil, [α]D25 -67.76 (CHCl3). Calc.: C 65.26, H 8.35, F 9.83; Found: C 65.46, H 8.47, F 9.60. |
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